tag:theconversation.com,2011:/id/topics/australian-red-cross-blood-service-40450/articlesAustralian Red Cross Blood Service – The Conversation2022-07-24T20:01:44Ztag:theconversation.com,2011:article/1835212022-07-24T20:01:44Z2022-07-24T20:01:44ZPeople who lived in the UK in the ‘mad cow disease’ years may now be able to give blood. The risk of vCJD is tiny<figure><img src="https://images.theconversation.com/files/466871/original/file-20220603-20-xfv97z.jpg?ixlib=rb-1.1.0&rect=0%2C2%2C998%2C444&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/woman-medical-mask-sits-chair-donates-2123764988">Shutterstock</a></span></figcaption></figure><p>From today, eligible people who were in the United Kingdom in the 80s and 90s will be able to donate blood in Australia again.</p>
<p>That’s because the risk of acquiring variant Creutzfeldt-Jakob disease (vCJD) from blood transfusions in Australia is incredibly tiny. </p>
<p>We calculated that risk was about one in 1.4 billion, <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/vox.13290">publishing our research</a> in the journal <em>Vox Sanguinis</em>.</p>
<p>The removal of restrictions, which have been in place for more than 20 years, means about 750,000 more Australians can now potentially donate blood.</p>
<p>This is at a time when there is a <a href="https://www.abc.net.au/news/2022-05-31/australia-blood-stocks-plummet-due-to-covid-flu/101113510">shortage of blood donations</a> due to donors sick with COVID or flu.</p>
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<h2>Remind me again, what is vCJD?</h2>
<p>Researchers identified vCJD as a new and emerging fatal neurological disease <a href="https://pubmed.ncbi.nlm.nih.gov/8598754/">in 1996</a>. It has since been associated with 233 cases <a href="https://pubmed.ncbi.nlm.nih.gov/11283320/">worldwide</a>, with 178 of those in the UK. </p>
<p>Once infected, people show no symptoms for many years. But when they do, there are psychiatric symptoms, such as depression. Then there are sensory symptoms, such as pain, followed by neurological abnormalities. People usually die about a year after symptoms start.</p>
<p>Transmission has been mainly via eating beef from cattle with bovine spongiform encephalitis (or BSE, commonly referred to as “mad cow disease”) in the UK during the 80s and 90s. </p>
<p>Mad cow disease had been spread by contaminated stock feed (cattle had been fed with contaminated beef products) before regulations were tightened and implemented, from 1996.</p>
<p>Over this time, an estimated <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7130755/">180,000</a> infected cattle had entered the UK human food chain.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/rare-and-deadly-creutzfeldt-jakob-disease-remains-a-bit-of-a-medical-mystery-44408">Rare and deadly, Creutzfeldt-Jakob disease remains a bit of a medical mystery</a>
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<h2>How is this connected to giving blood?</h2>
<p>There is no easy test for vCJD and infected people don’t know they have it until they have symptoms. This pre-symptomatic phase can be as long as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3310634/">several decades</a>. So there was speculation there could be unidentified people with vCJD, but exactly how many was unclear.</p>
<p>This is a potential public health issue as people who don’t know they have vCJD could transmit to others through blood, or tissue and organ donations.</p>
<p>This is why people who were in the UK between 1980 and 1996 for six months or more have been unable to give blood in Australia, since December 2000. Other countries had similar bans.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/466879/original/file-20220603-24-1esy45.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Blood bag hanging in operating theatre while surgeons operating" src="https://images.theconversation.com/files/466879/original/file-20220603-24-1esy45.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/466879/original/file-20220603-24-1esy45.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/466879/original/file-20220603-24-1esy45.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/466879/original/file-20220603-24-1esy45.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/466879/original/file-20220603-24-1esy45.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/466879/original/file-20220603-24-1esy45.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/466879/original/file-20220603-24-1esy45.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">People who didn’t know they had vCJD could have transmitted to others via a blood transfusion.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/giving-blood-during-operation-222697294">Shutterstock</a></span>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-animal-experiments-to-saving-lives-a-history-of-blood-transfusions-80391">From animal experiments to saving lives: a history of blood transfusions</a>
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</em>
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<h2>So what’s changed?</h2>
<p>Since the peak of the vCJD epidemic in 2000, when there were <a href="http://www.cjd.ed.ac.uk/sites/default/files/figs.pdf">28 deaths in the UK</a>, there has been a rapid decline in recorded cases, with only two worldwide since 2015. These numbers are much lower than modelled predictions. </p>
<p>Because there have been no BSE or vCJD cases in Australia, lower-than-predicted vCJD case numbers generally, and the ongoing change in the proportion of people in Australia who were exposed to vCJD, we recently reassessed the risk of vCJD in Australian blood donors.</p>
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Read more:
<a href="https://theconversation.com/australias-ethnic-face-is-changing-and-so-are-our-blood-types-113454">Australia’s ethnic face is changing, and so are our blood types</a>
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<h2>The risk is tiny, the benefits large</h2>
<p>We looked at a range of scenarios, including different assumptions about the numbers of people with vCJD, infectiousness and incubation periods.</p>
<p>Using modelling, we predicted a blood donation from an Australian with vCJD would occur once every 65 years, but this rate decreases over time.</p>
<p>If that donated blood was used in a transfusion today, there would be about a one in 1.4 billion chance of the recipient developing vCJD.</p>
<p>In other words, there is virtually no increased risk of vCJD transmission via transfusion (and this is decreasing). Lifting the ban on UK donors would increase the donor pool by 750,000 newly eligible people. </p>
<p>Assuming donation at the current rate, this would result in a gain of around 58,000 blood donations annually.</p>
<p>Our research was instrumental in supporting today’s opening up of blood donations, <a href="https://www.lifeblood.com.au/news-and-stories/media-centre/media-releases/tga-approval-lift-mad-cow-blood-donation-ban-people-who-lived-in-uk">as approved</a> by the Therapeutic Goods Administration earlier this year and subsequently supported by Australian governments.</p>
<p>The Food and Drug Administration has also <a href="https://www.fda.gov/regulatory-information/search-fda-guidance-documents/recommendations-reduce-possible-risk-transmission-creutzfeldt-jakob-disease-and-variant-creutzfeldt">recommended</a> removing similar restrictions on blood donors in the United States.</p>
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<p><em>The authors acknowledge the assistance of Veronica Hoad and Alison Gould from Lifeblood in drafting and reviewing the article.</em></p>
<p><em>Contact <a href="https://www.lifeblood.com.au">Lifeblood</a> to donate blood in Australia.</em></p><img src="https://counter.theconversation.com/content/183521/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Clive Seed is Senior Blood Safety Analyst, Clinical Services and Research, Australian Red Cross Lifeblood.</span></em></p><p class="fine-print"><em><span>This work was funded by and NH&MRC Partnership Grant (APP1151959)</span></em></p><p class="fine-print"><em><span>Hamish McManus does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>We calculated there was a one in 1.4 billion chance of someone contracting vCJD from a blood transfusion. And that risk will get even smaller with time.Hamish McManus, Biostatistician, Kirby Institute, UNSW SydneyClive Seed, Adjunct lecturer in allograft transmissible infections, medical school (surgery), The University of Western AustraliaMatthew Law, Professor and Program Head, Biostatistics and Databases Program, Kirby Institute, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1345412020-03-30T05:40:29Z2020-03-30T05:40:29ZIn the time of coronavirus, donating blood is more essential than ever<figure><img src="https://images.theconversation.com/files/323781/original/file-20200329-146678-1czjfo8.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3594%2C2392&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Blood is like milk, not toilet paper. You can’t just buy a lot of it and save it for later – you need to have a regular, fresh supply for patients who need it.</p>
<p>At the moment, fewer Australians are donating blood than usual. To a degree, we can understand why.</p>
<p>But blood donation is an essential health service, even during the coronavirus pandemic. </p>
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Read more:
<a href="https://theconversation.com/how-coronavirus-is-upsetting-the-blood-supply-chain-133424">How coronavirus is upsetting the blood supply chain</a>
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<p>Donor centres have implemented new measures to ensure the safety of staff, donors and patients receiving transfusions during this time.</p>
<p>If you’re healthy, there’s a good chance you’ll be eligible to donate.</p>
<h2>Why do we need more donors now?</h2>
<p>We need blood and plasma products <a href="https://www.donateblood.com.au/learn#how-your-blood-is-used">every day</a> to support cancer patients, <a href="https://mytransfusion.com.au/reasons-transfusion/pregnancy-childbirth">new mums and babies</a>, people with immune deficiencies or blood diseases, and people who need surgery or have suffered trauma. </p>
<p>We’re currently seeing an increase in cancellations and people rescheduling their appointments. Around 900 donors are cancelling appointments each day, up from 800 earlier this month. </p>
<p>There are a number of reasons fewer people are giving blood than usual.</p>
<p>At the start of 2020, we saw a strong response from donors who came forward as a way to help with the nation’s bushfire response. We’ve seen this <a href="https://www.hbs.edu/faculty/Pages/item.aspx?num=52492">response to major events</a> before and we know it can <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/deci.12381">affect the supply chain</a> down the track. Because these donors need to wait 12 weeks before they can donate blood again, there are fewer people available to give blood right now. </p>
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Read more:
<a href="https://theconversation.com/coronavirus-are-people-with-blood-group-a-really-at-higher-risk-of-catching-covid-19-134181">Coronavirus: are people with blood group A really at higher risk of catching COVID-19?</a>
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<p>Relating to coronavirus specifically, as people follow advice to stay home except for essential activities, they may be less inclined to donate blood. </p>
<p>And if the virus spreads to more people, fewer people may be eligible to donate because of new restrictions to keep our patients, staff, and donor centres safe. </p>
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<img alt="" src="https://images.theconversation.com/files/323874/original/file-20200330-146689-101ez9g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/323874/original/file-20200330-146689-101ez9g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/323874/original/file-20200330-146689-101ez9g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/323874/original/file-20200330-146689-101ez9g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/323874/original/file-20200330-146689-101ez9g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/323874/original/file-20200330-146689-101ez9g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/323874/original/file-20200330-146689-101ez9g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A person having surgery might need a blood transfusion.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
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<p>Based on our forecasts for demand from Australian health providers, <a href="https://www.lifeblood.com.au/">Australian Red Cross Lifeblood</a> needs an additional 7,000 donors to make appointments to donate blood through to Easter Monday to prevent a shortage.</p>
<h2>Who can donate?</h2>
<p>Australia currently has around <a href="https://www.donateblood.com.au/sites/default/files/Lifeblood-Annual-Report-2018-19.pdf">500,000 blood donors</a>, but millions of others may be eligible to donate. </p>
<p>Normally, if you’re aged between 18 and 76, weigh over 50kg and are healthy and well, you may be eligible. However, in keeping with government advice we encourage those aged 70 and over to postpone their donation during this period. There are other <a href="https://www.donateblood.com.au/eligibility">eligibility criteria</a> which remain in place to ensure our patients and donors are safe from the risks we already understand.</p>
<p>Notably, there’s no evidence coronavirus or other respiratory viruses can be transmitted by blood transfusion. </p>
<p>But to be on the safe side, Lifeblood’s strict screening process means people who are unwell can’t donate.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/coronavirus-how-long-does-it-take-to-get-sick-how-infectious-is-it-will-you-always-have-a-fever-covid-19-basics-explained-132963">Coronavirus: how long does it take to get sick? How infectious is it? Will you always have a fever? COVID-19 basics explained</a>
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<p>During the pandemic, Lifeblood has introduced new rules to protect the safety of staff, donors and patients, in line with recent recommendations from the <a href="https://www.who.int/publications-detail/maintaining-a-safe-and-adequate-blood-supply-during-the-pandemic-outbreak-of-coronavirus-disease-(covid-19)">World Health Organisation</a>:</p>
<ul>
<li><p>anyone who has returned from overseas is unable to donate for 28 days after their return</p></li>
<li><p>people who have been in close contact with a confirmed case of COVID-19 will have to wait 28 days before donating</p></li>
<li><p>people who have been confirmed as having COVID-19 will not be able to donate until they are cleared by their doctor plus undergo an additional recovery period.</p></li>
<li><p>people with mild cold-like symptoms will be unable to donate until they are fully recovered. </p></li>
</ul>
<h2>Am I allowed to travel to a donor centre, and is it safe?</h2>
<p>As many states in Australia have limited non-essential activities, it’s important to understand blood and plasma donation is vital, and travel and venue restrictions don’t prevent people from giving blood.</p>
<p>Donor centres are strictly regulated spaces, monitored regularly by the Therapeutic Goods Administration. There’s a <a href="https://www.tga.gov.au/sites/default/files/manuf-cgmp-human-blood-tissues-2013.pdf">specific code</a> that sets out requirements for staff, premises, collection procedures, quality control and testing, among other things.</p>
<p>Staff adhere to strict sanitation protocols including wearing gloves, wiping down surfaces after every donation and using single use sterile collection kits for every donation.</p>
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<p>In addition to the usual hygiene practices and new restrictions to who can donate, Lifeblood is implementing <a href="https://www.donateblood.com.au/page/coronavirus-update">further measures</a> to help protect donors and staff, including: </p>
<ul>
<li><p>increased disinfecting of frequently used items</p></li>
<li><p>providing additional hand sanitiser for donors to use</p></li>
<li><p>additional daily disinfection of all areas in our centres including the donation floor, refreshment areas, reception and more</p></li>
<li><p>restricting non-donating visitors to our centres (so only staff and donors are allowed in)</p></li>
<li><p>providing public health information consistent with the latest official coronavirus advice in every centre </p></li>
<li><p>implementing social distancing in our centres wherever possible, ensuring all donors are at least 1.5 metres away from all other donors.</p></li>
</ul>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/australias-ethnic-face-is-changing-and-so-are-our-blood-types-113454">Australia’s ethnic face is changing, and so are our blood types</a>
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<p>We’re appealing to anyone who has an appointment booked and who feels well to keep it. </p>
<p>If you’re a blood donor and haven’t made your next appointment, you can help by booking one in the next few weeks.</p>
<p>If you’re a blood donor who gave more than month ago, you may be able to donate plasma now.</p>
<p>And if you’ve never donated before, now is a great time to become a donor and help us maintain the nation’s blood supplies. </p>
<p><em>You can make an appointment <a href="https://www.donateblood.com.au/">online</a> or call 13 14 95.</em></p><img src="https://counter.theconversation.com/content/134541/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Irving is Director, Research and Development at Australian Red Cross Lifeblood.
Australian governments fund Australian Red Cross Lifeblood to provide blood, blood products and services to the Australian community.</span></em></p>Fewer people are donating blood during the coronavirus pandemic. But donor centres have implemented new rules to ensure staff, donors and patients remain safe.David Irving, Adjunct Professor, University of Technology SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/754602017-07-27T20:14:40Z2017-07-27T20:14:40ZWhy are only some viruses transmissible by blood and how are they actually spread?<figure><img src="https://images.theconversation.com/files/171303/original/file-20170529-25222-j5xsv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The most important blood borne viruses for human health are the human immunodeficiency virus (HIV), Hepatitis B and Hepatitis C.</span> <span class="attribution"><span class="source">from www.shutterstock.com.au</span></span></figcaption></figure><p><em>This week we’re running a series in collaboration with the Australian Red Cross Blood Service looking at blood: what it actually does, why we need it, and what happens when something goes wrong with the fluid that gives us life. Read other articles in the series <a href="https://theconversation.com/au/topics/blood-series-39533">here</a>.</em></p>
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<p>Since the 1980s, most of us have been aware we need to be careful when coming into contact with the blood of others, because some viruses can be transmitted in this way. But why is it only some viruses are transmissible by blood, and how does the virus actually move from person to person?</p>
<p>Viruses are non-living, infectious agents that use our own cells to function and replicate. Unlike bacteria and fungi, they can’t do this on their own, and must find an appropriate host cell they can enter and replicate in.</p>
<p>Blood-borne viruses are those found at levels that can be detected in an infected person’s blood. They can be passed from person to person by blood, and in some cases other bodily fluids, including semen and breast milk. They can be transmitted from an infected person by intravenous drug use, a needle stick injury with contaminated needles, blood transfusions and sexual intercourse. They can also be transmitted from mother to child, before, during or even after birth.</p>
<p>The most important blood borne viruses for human health are the human immunodeficiency virus (<a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/hiv-and-aids">HIV</a>), <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/hepatitis-b">Hepatitis B</a> and <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/hepatitis-c">Hepatitis C</a>. These viruses persist in the blood long-term or for life.</p>
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<a href="https://images.theconversation.com/files/171296/original/file-20170529-25201-1bhyruv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171296/original/file-20170529-25201-1bhyruv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/171296/original/file-20170529-25201-1bhyruv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171296/original/file-20170529-25201-1bhyruv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171296/original/file-20170529-25201-1bhyruv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171296/original/file-20170529-25201-1bhyruv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1130&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171296/original/file-20170529-25201-1bhyruv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1130&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171296/original/file-20170529-25201-1bhyruv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1130&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Most of us know blood-borne viruses can be spread by intravenous drug use and needle stick injuries.</span>
<span class="attribution"><span class="source">from www.shutterstock.com.au</span></span>
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</figure>
<p>Many other viruses may be found briefly in blood, but they generally don’t persist and are not considered significant “blood-borne” pathogens. Any infectious agent with a blood-borne, or “viraemic” phase has the potential for blood borne transmission, and so may be important for blood transfusions. </p>
<p>For many infections, this viraemic period persists until the immune system is able to cure the infection by killing all infected cells. For some viruses, including Zika and Dengue, the viraemic phase lasts a matter of days. For other viruses such as Hepatitis B and C, or HIV, this viraemic phase persists. </p>
<p>Treatment of blood-borne viruses aims to stop the virus replicating. If a blood-borne virus is not detectable in blood, then a person is generally considered non-infectious. </p>
<h2>How viruses spread through blood</h2>
<p>HIV infection can occur when a person is exposed to this virus. Typically, this involves sexual contact or direct blood to blood contact, either via an open wound or penetration of skin by a contaminated needle. </p>
<p>The virus then travels to the lymph nodes, where it enters cells of the immune system called “T cells”. Here, a cat and mouse battle begins. The virus and immune system use complex tactics to outsmart each other. </p>
<p>Perhaps the greatest of these tricks belong to HIV; the virus incorporates itself into the DNA of host T cells, and hides from the immune system in protected sites, such as the central nervous system. This makes it impossible to clear the virus from the body completely, and without treatment HIV remains detectable in blood. </p>
<p>The cells responsible for attacking the virus instead produce new virus particles and attack other, infected, T cells. Without treatment, this leads to destruction of the immune system, unusual infections and a syndrome known as the acquired immune deficiency syndrome (AIDS), which is almost invariably fatal.</p>
<p>In contrast, <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/flu-influenza">influenza</a> is spread by respiratory droplets. Virus particles are transmitted when an infected person coughs or sneezes. Droplets are inhaled by a new host, the virus binds to target receptors on the respiratory tract surface, and replicates in cells of the respiratory tract.</p>
<p>Unlike HIV, influenza cannot insert itself into the host’s genes. Instead, the immune system detects infection, turns off viral reproduction and clears infected cells. While medications are available to aid this process, they are often unnecessary, as the immune system is often able to cure influenza independently. Previous influenza infection or vaccination provides some immune memory and provides protection and faster immune clearance of the virus. </p>
<p>Influenza can be found in the blood for a brief period of time, particularly in severe cases, when the person is showing symptoms of flu. Although blood transfusions are not routinely tested for influenza infection, blood donors are asked not to donate if they are unwell.</p>
<h2>Transmission via transfusion</h2>
<p>Blood transfusions are an important, lifesaving component of modern medicine. But this technology is associated with a small degree of risk, including blood-borne virus transmission.</p>
<p>In <a href="http://www.donateblood.com.au/eligibility/blood-testing-and-safety">Australia</a>, blood transfusions are extremely safe, made secure by legislative, scientific, and practical measures. Legislation precludes certain <a href="http://www.donateblood.com.au/eligibility#can-i-give-blood">groups</a> of individuals from donating blood, with a view to minimising the chance of a person with a blood-borne virus donating.</p>
<p>Donated blood is tested for the most important blood-borne viruses, including HIV, Hepatitis B and Hepatitis C. These tests are highly sensitive, and detect close to 100% of these infections.</p>
<p>Blood products destined for recipients with weakened immune systems, like transplant recipients, are tested for additional viruses that are not considered problematic in most people.</p>
<p>Practically, a number of important safeguards are also in place to ensure that the right person gets compatible blood, at the right time.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/5ZMuPciBVy8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The journey of blood.</span></figcaption>
</figure>
<hr>
<p><em><strong>Read other articles in the series:</strong></em></p>
<p><em><a href="https://theconversation.com/essays-on-blood-why-do-we-actually-have-it-75064">Essays on blood: why do we actually have it?</a></em></p>
<p><em><a href="http://theconversation.com/from-animal-experiments-to-saving-lives-a-history-of-blood-transfusions-80391">From animal experiments to saving lives: a history of blood transfusions</a></em></p>
<p><em><a href="http://theconversation.com/explainer-whats-actually-in-our-blood-75066">Explainer: what’s actually in our blood?</a></em></p>
<p><a href="http://theconversation.com/blood-groups-beyond-a-b-and-o-what-are-they-and-do-they-matter-75063"><em>Blood groups beyond A, B and O: what are they and do they matter?</em></a></p>
<p><em><a href="http://theconversation.com/what-can-go-wrong-in-the-blood-a-brief-overview-of-bleeding-clotting-and-cancer-76400">What can go wrong in the blood? A brief overview of bleeding, clotting and cancer</a></em></p>
<p><a href="http://theconversation.com/blood-tests-and-diagnosing-illness-what-can-blood-tell-us-about-whats-happening-in-our-body-80327"><em>Blood tests and diagnosing illness: what can blood tell us about what’s happening in our body?</em></a></p><img src="https://counter.theconversation.com/content/75460/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Why is it only some viruses are transmissible by blood, and how does the virus actually move from person to person?David Griffin, Advanced Trainee, Infectious Diseases and General Medicine, The Peter Doherty Institute for Infection and ImmunityThomas Schulz, Infectious diseases and general physician, The Peter Doherty Institute for Infection and ImmunityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/803272017-07-26T20:15:02Z2017-07-26T20:15:02ZBlood tests and diagnosing illness: what can blood tell us about what’s happening in our body?<figure><img src="https://images.theconversation.com/files/176715/original/file-20170704-12293-nwqqm7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Blood permeates every tissue in the body, meaning just a few spoonfuls can tell us a lot about our health. </span> <span class="attribution"><span class="source">from www.shutterstock.com.au</span></span></figcaption></figure><p><em>This week we’re running a series in collaboration with the Australian Red Cross Blood Service looking at blood: what it actually does, why we need it, and what happens when something goes wrong. Read other articles in the series <a href="https://theconversation.com/au/topics/blood-series-39533">here</a>.</em></p>
<hr>
<p>Doctors have continually sought better ways of determining what is wrong with a patient. When you visit a GP’s office or emergency department with an unknown illness, a doctor will commonly draw some blood to gain a better idea of what’s going on inside your body. Blood is perhaps the most important window through which we can peer into a person’s health or illness.</p>
<p>About 7% of our body weight is our blood, and our heart spits out about five litres of blood every minute. Oxygenated blood leaves the left side of the heart via the aorta and the arteries - which permeate every tissue in the body - and returns to the right side of the heart via the veins. From the right side of the heart, blood is pumped into the lungs where it is oxygenated, returning to the left side of the heart.</p>
<p>In about two tablespoons of blood there’s a lot we can tell about our health.</p>
<h2>What blood can tell us</h2>
<p>When someone presents at an emergency department, the initial panel of tests will include a full blood count. This details the red blood cell count, white blood cell count and platelets; electrolytes (the substance in our blood that carries an electric charge that is vital for life) to measure kidney function; liver function tests and “C-reactive protein” which can tell us if there is inflammation somewhere in the body.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/177464/original/file-20170710-5553-yu4kic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/177464/original/file-20170710-5553-yu4kic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/177464/original/file-20170710-5553-yu4kic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/177464/original/file-20170710-5553-yu4kic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/177464/original/file-20170710-5553-yu4kic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/177464/original/file-20170710-5553-yu4kic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/177464/original/file-20170710-5553-yu4kic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/177464/original/file-20170710-5553-yu4kic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Our blood can tell us how many of our organs are functioning.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
</figcaption>
</figure>
<p>From these tests we can determine things like the presence of anaemia (low red blood cells from various causes), infection, kidney failure and liver disease. Often the results of these tests will trigger further testing. For example, the presence of anaemia will usually lead to testing for iron deficiency, possibly vitamin B12 and folate, screening for haemolysis (destruction of red blood cells) and a measure of how well the bone marrow, which makes red blood cells, is responding. </p>
<p>If infection is suspected, blood will be drawn and transferred into a bottle that enables bacteria to grow. Bacteria in the blood is called septicaemia. The identification of the bacteria responsible significantly helps in the management, meaning the right antibiotics can be delivered to the patient.</p>
<hr>
<p><a href="https://theconversation.com/from-animal-experiments-to-saving-lives-a-history-of-blood-transfusions-80391"><em>Infographic - From animal experiments to saving lives: a history of blood transfusions</em></a></p>
<hr>
<p>Bruising or excessive bleeding will prompt assessment of platelets and clotting. Platelets are the first responders to injury, and if they are low or not functioning properly, they will allow bleeding to proceed unchecked. To tell if blood is clotting normally we need an additional teaspoon of blood. These clotting factors are synthesised in the liver, so they can also give us a warning about liver disease.</p>
<p>As a kidney specialist, my personal favourite are the electrolytes. Together with a urine test, blood electrolytes can measure someone’s kidney disease from stage one through to five. As kidney function declines, potassium levels increase in the blood and can reach dangerous levels. A high potassium count can cause a potentially fatal heart arrhythmia.</p>
<p>Liver function tests provide information on what the liver is producing and excreting - abnormalities of liver function could mean gall stones or hepatitis. Viral causes of hepatitis, such as Hepatitis B and C, can quickly be checked in the blood. We can also find out how recently the infection was acquired and whether chronic infection persists.</p>
<p>Cardiac enzymes in the blood tell us if a patient has had a heart attack. The enzymes are proteins released from damaged heart muscle, so the higher the level, the greater the damage to the heart.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/179116/original/file-20170721-30878-unhpag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/179116/original/file-20170721-30878-unhpag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/179116/original/file-20170721-30878-unhpag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/179116/original/file-20170721-30878-unhpag.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/179116/original/file-20170721-30878-unhpag.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/179116/original/file-20170721-30878-unhpag.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/179116/original/file-20170721-30878-unhpag.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/179116/original/file-20170721-30878-unhpag.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Blood is an incredible window into the workings of the human body.</span>
<span class="attribution"><span class="source">Blood on Silk / Buy Sell by Fiona Davies (AUS) Courtesy of the artist as part of Science Gallery Melbourne’s BLOOD exhibition</span></span>
</figcaption>
</figure>
<h2>What can’t blood tell us?</h2>
<p>The repertoire of blood tests available to the treating doctor is vast. Other blood tests include screening for autoimmune disease, monitoring the response of cancers to treatment with tumour markers, assessing reproductive function, screening for genetic disorders during pregnancy and diagnosing pregnancy itself.</p>
<p>Despite this, sometimes a diagnosis remains elusive – frustrating for the patient and doctor alike. Neurological disease such as stroke, motor neurone disease, Alzheimer’s and multiple sclerosis aren’t diagnosable from blood tests. Similarly, the diagnoses of depression, schizophrenia, ADHD and autism lack a specific blood diagnostic marker.</p>
<p>The huge array of blood tests available to the clinician aid in a rapid diagnosis in many instances. But the choice and the interpretation of the test needs to be considered in light of the patient and their presenting symptoms. As the old adage in medicine says: treat the person and not the numbers.</p>
<hr>
<p><em><strong>Read other articles in the series:</strong></em></p>
<p><em><a href="https://theconversation.com/essays-on-blood-why-do-we-actually-have-it-75064">Essays on blood: why do we actually have it?</a></em></p>
<p><em><a href="http://theconversation.com/from-animal-experiments-to-saving-lives-a-history-of-blood-transfusions-80391">From animal experiments to saving lives: a history of blood transfusions</a></em></p>
<p><em><a href="http://theconversation.com/explainer-whats-actually-in-our-blood-75066">Explainer: what’s actually in our blood?</a></em></p>
<p><a href="http://theconversation.com/blood-groups-beyond-a-b-and-o-what-are-they-and-do-they-matter-75063"><em>Blood groups beyond A, B and O: what are they and do they matter?</em></a></p>
<p><em><a href="http://theconversation.com/what-can-go-wrong-in-the-blood-a-brief-overview-of-bleeding-clotting-and-cancer-76400">What can go wrong in the blood? A brief overview of bleeding, clotting and cancer</a></em></p><img src="https://counter.theconversation.com/content/80327/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Karen Dwyer does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Blood is perhaps the most important window through which we can peer into a person’s health or illness.Karen Dwyer, Deputy Head, School of Medicine, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/764002017-07-25T20:08:20Z2017-07-25T20:08:20ZWhat can go wrong in the blood? A brief overview of bleeding, clotting and cancer<figure><img src="https://images.theconversation.com/files/170508/original/file-20170523-8895-ekibmg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Our blood flows through our every organ and gives us life. So problems can have wide-ranging consequences. </span> <span class="attribution"><span class="source">from www.shutterstock.com.au</span></span></figcaption></figure><p><em>This week we’re running a series in collaboration with the Australian Red Cross Blood Service looking at blood: what it actually does, why we need it, and what happens when something goes wrong with the fluid that gives us life. Read other articles in the series <a href="https://theconversation.com/au/topics/blood-series-39533">here</a>.</em></p>
<hr>
<p>While blood is essential for human life, there are many things that can go wrong. And as it travels around the body and flows through every organ, problems in the blood can have wide-ranging implications for our health. There are countless problems that can occur in this vital fluid; here, we’ll have a look at the most common - bleeding disorders, clotting disorders and blood cancers.</p>
<h2>Bleeding disorders</h2>
<p>If our blood vessels are damaged in some way, the blood contains platelets and many clotting factors (or proteins) that will form a clot in order to stem blood loss from our veins. If the number or function of these platelets or clotting proteins is reduced, this will lead to a “<a href="http://journals.lww.com/anesthesia-analgesia/Fulltext/2007/05000/Hemostasis_and_Thrombosis__Basic_Principles_and.93.aspx">bleeding disorder</a>”.</p>
<p>Platelets are produced by the marrow in our bones, and clotting factors by our liver. Both are affected by our individual genetic makeup. Therefore genetic abnormalities that adversely affect the function of either organ can result in bleeding disorders. Major trauma to blood vessels can also cause excessive bleeding that requires surgery.</p>
<p>Patients with disorders of their platelets typically present with bruises, fine spots on the limbs or trunk, or recurrent nose or gum bleeds (called “muco-cutaneous bleeding”).</p>
<p>Those with <a href="http://journals.lww.com/anesthesia-analgesia/Fulltext/2007/05000/Hemostasis_and_Thrombosis__Basic_Principles_and.93.aspx">deficiencies in clotting factors</a> may have joint, muscle or critical organ bleeds such as an intracranial haemorrhage (a bleed inside the skull). Women can present with excessive menstrual bleeding. Patients with a hereditary bleeding disorder often have a family history of excessive bleeding. Those patients with milder forms of bleeding disorders might present with excessive bleeding for the first time only after surgical procedures or major trauma.</p>
<p>The diagnosis of bleeding disorders is complex and requires a careful assessment for an excessive bleeding history, the presence (or absence) of a family history, and extensive laboratory evaluation of the platelet and clotting factors by a blood specialist, called a haematologist.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/5ZMuPciBVy8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The journey of blood.</span></figcaption>
</figure>
<p>A bleeding disorder you’ve probably heard of is haemophilia. This is a bleeding disorder caused when someone has less than 40% of the normal level of clotting factors (specifically, factor VIII). This is relatively rare, with about one in 10,000 people (<a href="https://www.haemophilia.org.au/about-bleeding-disorders/haemophilia">0.01% of Australians</a>) suffering from the disorder. Haemophilia is associated with joint and muscle bleeds, and sufferers need this clotting factor to be replaced in their blood for the rest of their lives.</p>
<p>The treatment of bleeding disorders depends on the diagnosis and severity. Those with a deficiency in a clotting factor can receive a factor concentrate replacement, the frequency of which depends on its severity. Treatment of platelet defects is complex, but can include platelet transfusion. Tranexamic acid is a drug that can also be used to help prevent bleeding. </p>
<p>Patients with hereditary bleeding disorders can bleed significantly (and to death) if not given the correct treatment to stop the bleeding or prevent bleeding prior to surgeries.</p>
<h2>Clotting disorders</h2>
<p>While it’s necessary for our blood to be able to form clots, if clots form inside blood vessels when no injury has occurred, this can have significant consequences. “Thrombosis” refers to the formation of a blood clot inside a blood vessel, impeding blood flow. </p>
<p>A part of the clot can break off and travel further around the body, a process called “embolism”. Thrombosis can develop in the arteries (vessels transporting blood from the heart to the organs) or the veins (vessels transporting blood from the organs to the heart). </p>
<p>A blockage in the arteries (arterial thrombosis) blocks the blood supply, causing a shortage of oxygen and glucose that are required to keep our tissues alive. Venous thrombosis (blockages in the veins) impede the blood flow from the organs to the heart. In both instances, embolism can occur.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/177039/original/file-20170706-26513-okgk71.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/177039/original/file-20170706-26513-okgk71.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/177039/original/file-20170706-26513-okgk71.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/177039/original/file-20170706-26513-okgk71.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/177039/original/file-20170706-26513-okgk71.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/177039/original/file-20170706-26513-okgk71.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/177039/original/file-20170706-26513-okgk71.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/177039/original/file-20170706-26513-okgk71.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Blood needs to clot so we don’t lose all of it when trauma damages our blood vessels.</span>
<span class="attribution"><span class="source">from www.shutterstock.com.au</span></span>
</figcaption>
</figure>
<p>A common clotting condition that involves the veins is “venous thromboembolism” or VTE, which includes both deep vein thrombosis (DVT - a blood clot in a deep vein, often in the legs) and pulmonary embolism (PE - a blockage in the lungs). This is where the blood clot moves from a deep vein to the lungs. </p>
<p>Surgery, major trauma or prolonged immobility can all be causes of venous thromboembolism. But there are <a href="http://onlinelibrary.wiley.com/store/10.1111/j.1469-8749.2001.tb00151.x/asset/j.1469-8749.2001.tb00151.x.pdf;jsessionid=93B25B0BD5D0ACE9DC814B8DB020722E.f02t03?v=1&t=j352g66p&s=18324c10bf11174a27dc7d92977219be455d4c56">other risk factors</a> that alter the constituents of the blood, to promote thrombosis. These include the oestrogen oral contraceptive pill, pregnancy, inflammatory bowel disease, heritable thrombophilia (an inherited abnormality making clots more likely to form), and several others.</p>
<p>Deep vein thrombosis causes leg pain, swelling and redness, while pulmonary embolisms cause chest pain, shortness of breath, coughing up blood (haemoptysis) or collapse. All of these symptoms can be caused by other things, so thorough investigations are needed to confirm the diagnosis.</p>
<hr>
<p><a href="https://theconversation.com/from-animal-experiments-to-saving-lives-a-history-of-blood-transfusions-80391"><em>Infographic - From animal experiments to saving lives: a history of blood transfusions</em></a></p>
<hr>
<p>The treatment for these conditions is principally to rebalance the coagulation system using anticoagulants. Until recently, the only oral anticoagulant was warfarin, a drug that can have significant food and drug interactions, hence requiring frequent blood testing to monitor its control. But new and superior anticoagulants (such as apixaban and rivaroxaban) have been created that don’t require regular blood tests. </p>
<p>They also appear to be <a href="https://www.ncbi.nlm.nih.gov/pubmed/24963045">safer with a lower risk</a> of major bleeding, including intracranial haemorrhage. Antidotes exist in case the patient bleeds (needs surgery or is in an accident) and needs clotting.</p>
<p>Clots in the arteries can lead to myocardial infarction (a blockage in the heart), and ischaemic strokes (a blockage in the brain) – both are part of cardiovascular disease. Smoking, high blood pressure, high blood cholesterol, diabetes, obesity and a family history <a href="http://journals.lww.com/anesthesia-analgesia/Fulltext/2007/05000/Hemostasis_and_Thrombosis__Basic_Principles_and.93.aspx">can increase the risk of clots</a> in the arteries. Heart attacks can lead to heart failure, while strokes can lead to loss of function and sensation of limbs, and both can lead to death. </p>
<p>So it’s important to address the risk factors to minimise the risk of these occurring. If they do develop, antiplatelet medications (such as aspirin) and others can be prescribed to prevent it from happening again. Some patients have to have stents placed where the blockage occurred to prevent it from recurring.</p>
<h2>Blood cancers</h2>
<p>Blood cancers occur when there is an uncontrolled growth of blood cells, which can infiltrate tissues and cause disease. The main types of blood cancer are leukaemia, lymphoma and myeloma. A haematologist also treats these types of cancers.</p>
<p>The symptoms of blood cancer differ depending on the type of blood cell that has turned malignant, and where they are present. </p>
<p>Leukaemia is a cancer of immature white blood cells that accumulate in the bone marrow and often spill out into the blood. Leukaemias are categorised as acute or chronic depending on how fast they grow. </p>
<p>Acute leukaemias are aggressive cancers that require intensive chemotherapy in hospital. For many patients, the only chance of cure is through bone marrow transplant, essentially replacing their entire blood cells and immune systems with that of another person, either a relative (usually a sibling) or even an unrelated but genetically compatible donor. </p>
<p>Acute leukaemia is the most common childhood cancer, and can often be cured. But in adults with increasing age, and particularly over 70, it becomes more difficult to cure.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/177040/original/file-20170706-26471-13zs7hi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/177040/original/file-20170706-26471-13zs7hi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/177040/original/file-20170706-26471-13zs7hi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/177040/original/file-20170706-26471-13zs7hi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/177040/original/file-20170706-26471-13zs7hi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/177040/original/file-20170706-26471-13zs7hi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/177040/original/file-20170706-26471-13zs7hi.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/177040/original/file-20170706-26471-13zs7hi.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Leukaemia is one of the most common blood cancers.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
</figcaption>
</figure>
<p>Chronic leukaemias tend to only occur in adults. They are slow growing and some types have no symptoms, meaning treatment isn’t necessary. If the cancer is progressing or causing symptoms, therapy is given as an outpatient (meaning they don’t have to stay in hospital).</p>
<p>Lymphomas are a group of blood cancers that arise in a type of blood cell called lymphocytes (a type of small white blood cell found in the immune system). It causes swellings in the glandular or “lymphatic” system that fights infections and removes toxins from the body. Lymphomas are the <a href="http://www.leukaemia.org.au/blood-cancers">most common type</a> of blood cancer.</p>
<p>There are two main types of lymphoma, characterised by the presence (or lack of) an abnormal cell called the Reed-Sternberg cell. If the cell is present it’s referred to as Hodgkin Lymphoma - named after the British physician who discovered it. Hodgkin lymphoma occurs mainly in adolescents and young adults and makes up about 10% of cases. </p>
<p><a href="http://www.aihw.gov.au/cancer/lymphoma/">About 90% of lymphomas</a> are “non-Hodgkin lymphoma”, which mainly arise in the elderly. Treatment is usually chemotherapy and sometimes radiotherapy. While survival rates for Hodgkin Lymphoma are over 80%, there are many different subtypes of non-Hodgkin lymphoma, and outcomes vary considerably between subtypes.</p>
<p>Myeloma is a cancer of mature white blood cells and affects the bone. It usually occurs in those over the age of 60, and is treatable with chemotherapy and, increasingly, newer and less toxic medications. However it remains generally incurable.</p>
<hr>
<p><em><strong>Read other articles in the series:</strong></em></p>
<p><em><a href="https://theconversation.com/essays-on-blood-why-do-we-actually-have-it-75064">Essays on blood: why do we actually have it?</a></em></p>
<p><em><a href="http://theconversation.com/from-animal-experiments-to-saving-lives-a-history-of-blood-transfusions-80391">From animal experiments to saving lives: a history of blood transfusions</a></em></p>
<p><em><a href="http://theconversation.com/explainer-whats-actually-in-our-blood-75066">Explainer: what’s actually in our blood?</a></em></p>
<p><a href="http://theconversation.com/blood-groups-beyond-a-b-and-o-what-are-they-and-do-they-matter-75063"><em>Blood groups beyond A, B and O: what are they and do they matter?</em></a></p><img src="https://counter.theconversation.com/content/76400/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Maher Gandhi receives research funding from the NHMRC (Australia), Leukaemia Foundation, Celgene, Bristol Myers Squibb and Gilead.</span></em></p><p class="fine-print"><em><span>Huyen Tran has received grant-in-aid funding from Australian Haemophilia Centres Directors' Organisation (AHCDO), Thrombosis & Haemostasis Society of Australia and New Zealand (THANZ), Novartis, and Roche. </span></em></p>An overview of the most common problems in our blood: bleeding disorders, clotting disorders and cancer.Maher Gandhi, Professor of Blood Cancer Research, The University of QueenslandHuyen Tran, Adjunct associate professor, Monash UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/750632017-07-25T20:08:04Z2017-07-25T20:08:04ZBlood groups beyond A, B and O: what are they and do they matter?<figure><img src="https://images.theconversation.com/files/171916/original/file-20170602-25676-10togkw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">We know about A, B and O - but there are hundreds of other blood groups.</span> <span class="attribution"><span class="source">from www.shutterstock.com.au</span></span></figcaption></figure><p><em>This week we’re running a series in collaboration with the Australian Red Cross Blood Service looking at blood: what it actually does, why we need it, and what happens when something goes wrong with the fluid that gives us life. Read other articles in the series <a href="https://theconversation.com/au/topics/blood-series-39533">here</a>.</em></p>
<hr>
<p>There are many molecules on the surface of red blood cells that vary between individuals, and these form the basis of blood groups. The most commonly recognised of these are the ABO blood groups, and Rh antigens (which are signified by the “positive” or “negative” that comes after A, B or O on your blood type).</p>
<p>What you may not know is that there are <a href="https://www.elsevier.com/books/the-blood-group-antigen-factsbook/reid/978-0-12-415849-8">34 other blood group systems with more than 300 known variants</a>. These are all classified by the “antigens” found on the surface of our red blood cells. Antigens are molecules (most often proteins, but also carbohydrates) capable of provoking our immune systems to attack. </p>
<p>People also have antibodies - the proteins that attack infections and other foreign bodies. So when a patient needs someone else’s blood transfused into them, we have to make sure they don’t have the type of antibodies that will attack the antigens on the blood the donor has provided for them.</p>
<p>We do this by identifying the blood group the antibody reacts with and then matching blood from donors whose blood type has been extensively tested and established. Additional blood typing is carried out when an antibody to a blood cell antigen has been identified in a patient.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/171934/original/file-20170602-25704-1y0cj34.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/171934/original/file-20170602-25704-1y0cj34.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/171934/original/file-20170602-25704-1y0cj34.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/171934/original/file-20170602-25704-1y0cj34.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/171934/original/file-20170602-25704-1y0cj34.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/171934/original/file-20170602-25704-1y0cj34.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/171934/original/file-20170602-25704-1y0cj34.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/171934/original/file-20170602-25704-1y0cj34.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Knowing what antigens we have in our blood is crucial in case of a transfusion. Unmatched blood could make our bodies attack the donated blood cells.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
</figcaption>
</figure>
<h2>What are some of these blood groups?</h2>
<p>The “<a href="https://www.ncbi.nlm.nih.gov/pubmed/20406014">MNS blood group antigens</a>” were discovered in the 1920s by Karl Landsteiner (the same scientist who discovered the ABO system). This is a complex blood group system found on some of the most important structural proteins on the surface of red cells. It’s common to find antibodies to the M blood group in the plasma of patients, as these are sometimes formed after infection, and testing is required to ensure the patient’s anti-M antibodies do not destroy donated red blood cells.</p>
<p>Another blood group, the “S/s variants”, are named after Sydney, where the blood group was discovered. This blood group is signified by a particular type of molecule on the red blood cells that is a target of the malaria parasite. Interestingly, some people from Africa do not have these molecules on the surface of their cells at all, making them less likely to contract malaria.</p>
<hr>
<p><a href="https://theconversation.com/from-animal-experiments-to-saving-lives-a-history-of-blood-transfusions-80391"><em>Infographic - From animal experiments to saving lives: a history of blood transfusions</em></a></p>
<hr>
<p>A blood group known as Duffy is also associated with infection by another type of malaria (known as <em>Plasmodium vivax</em>). When this protein is absent from the red blood cells, the cells are resistant to infection by the malaria parasite. This protein is absent from the blood cells of 90% of sub-Saharan Africans, conferring malaria resistance on this population. Antibodies to the Duffy antigens are commonly found in a patient’s plasma and are a cause of transfusion reactions if carefully matched antigen negative blood is not given.</p>
<p>The <a href="https://www.ncbi.nlm.nih.gov/books/NBK2270/">K antigen (colloquially called Kell)</a> was first detected in the 1940s as a result of a woman without the K antigen on her red blood cells being pregnant with a baby <em>with</em> the K antigen on the red blood cells. While almost all women post-partum have antibodies to some antigens found on the baby’s white blood cells, red cell antibodies are less common. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/178777/original/file-20170719-13606-lh1yrp.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/178777/original/file-20170719-13606-lh1yrp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/178777/original/file-20170719-13606-lh1yrp.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=418&fit=crop&dpr=1 600w, https://images.theconversation.com/files/178777/original/file-20170719-13606-lh1yrp.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=418&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/178777/original/file-20170719-13606-lh1yrp.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=418&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/178777/original/file-20170719-13606-lh1yrp.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=525&fit=crop&dpr=1 754w, https://images.theconversation.com/files/178777/original/file-20170719-13606-lh1yrp.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=525&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/178777/original/file-20170719-13606-lh1yrp.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=525&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Some people from Africa lack a certain molecule on their blood cells, meaning they can’t get malaria.</span>
<span class="attribution"><span class="source">Artwork: The Mums by Jipil Jung (Sth Korea), Courtesy of the artist as part of Science Gallery Melbourne’s BLOOD exhibition</span></span>
</figcaption>
</figure>
<p>Following the discovery of the K antigen, more antigens were also found in this blood group system, which is a common pattern of discovery in this field. The red cells of <a href="https://www.ncbi.nlm.nih.gov/books/NBK2270/">9% of the Caucasian population</a> have the K antigen on their surface. After the Rh antigens, anti-K is the most common antibody found in testing patients prior to transfusion. </p>
<p>Another blood group, Kidd, was named after the patient in whom it was discovered. The <a href="https://www.ncbi.nlm.nih.gov/books/NBK2272/">Kidd proteins are related to proteins in the kidney</a> that help get rid of waste from the body. For the Kidd blood group it’s very important to avoid damaging reactions, and therefore carefully matched antigen negative blood is given.</p>
<h2>How did we discover all these groups?</h2>
<p>The most common way these blood groups were discovered was through investigation of patients who had poor outcomes from transfusion. Their plasma has been used to study donors and find blood suitable for transfusion. This would then be used to prevent reactions in patients with similar antibodies. The chain of <a href="http://www.donateblood.com.au/research/solving-rare-blood-type-mysteries">discovering a problem</a> and then working out how to stop it happening again is the basis of testing blood prior to transfusion.</p>
<p>Although we don’t know the function of all the cell surface molecules that make up the blood group antigens, we do know some of them have functions elsewhere. For example, the Kell antigen is an enzyme (the biological catalysts). Other red cell antigens are involved in the structure of the cell membrane, and the transport of chemicals between the inside and outside of the cell. All antigens should be considered when matching blood for transfusion. </p>
<p>The field of blood group antigens is always growing, particularly with the application of modern genetic sequencing techniques. Using these techniques, the research team at the <a href="https://www.donateblood.com.au/research">Australian Red Cross Blood Service</a> have discovered at least three <a href="https://www.researchgate.net/publication/311422377_An_alloantibody_in_a_homozygous_GYPMur_individual_defines_JENU_MNS49_a_new_high-frequency_antigen_on_glycophorin_B_JENU_MNS49_A_NEW_HIGH-FREQUENCY_ANTIGEN_ON_GPB">new blood group antigens</a> in recent years, and have also deciphered the blood types of ancient people such as Denisovans and Neanderthals, based on their DNA sequence.</p>
<p><iframe id="tc-infographic-221" class="tc-infographic" height="720" src="https://cdn.theconversation.com/infographics/221/52c00dc381eaf2daed9ba8e6e893e59fcae733a9/site/index.html" width="100%" style="border: none" frameborder="0"></iframe></p>
<hr>
<p><em><strong>Read other articles in the series:</strong></em></p>
<p><em><a href="https://theconversation.com/essays-on-blood-why-do-we-actually-have-it-75064">Essays on blood: why do we actually have it?</a></em></p>
<p><em><a href="http://theconversation.com/from-animal-experiments-to-saving-lives-a-history-of-blood-transfusions-80391">From animal experiments to saving lives: a history of blood transfusions</a></em></p>
<p><em><a href="http://theconversation.com/explainer-whats-actually-in-our-blood-75066">Explainer: what’s actually in our blood?</a></em></p>
<p><em><a href="http://theconversation.com/what-can-go-wrong-in-the-blood-a-brief-overview-of-bleeding-clotting-and-cancer-76400">What can go wrong in the blood? A brief overview of bleeding, clotting and cancer</a></em></p><img src="https://counter.theconversation.com/content/75063/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Robert Flower works for the Australian Red Cross Blood Service. Australian governments fund the Australian Red Cross Blood Service for the provision of blood, blood products and services to the Australian community. He also receives funding from the Australian Research Council. </span></em></p>Why do we have blood groups and how are they discovered?Robert Flower, Associate Professor, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/750662017-07-24T20:12:06Z2017-07-24T20:12:06ZExplainer: what’s actually in our blood?<figure><img src="https://images.theconversation.com/files/170731/original/file-20170524-5786-oxlpch.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Our blood has more functions than we probably realise - all vital for life. </span> <span class="attribution"><span class="source">from www.shutterstock.com.au</span></span></figcaption></figure><p><em>This week we’re running a series in collaboration with the Australian Red Cross Blood Service looking at blood: what it actually does, why we need it, and what happens when something goes wrong with the fluid that gives us life. Read other articles in the series <a href="https://theconversation.com/au/topics/blood-series-39533">here</a>.</em></p>
<hr>
<p>Blood is vitally important for our body. As it’s pumped around our body through veins and arteries, it transports oxygen from our lungs to all of the other organs, tissues and cells that need it. Blood also removes waste products from our organs and tissues, taking them to the liver and kidneys, where they’re removed from the body.</p>
<p>About 45% of our blood consists of different types of cells and the other 55% is plasma, a pale yellow fluid. Blood transports nutrients, hormones, proteins, vitamins and minerals around our body, suspended in the plasma. They provide energy to our cells and also signal for growth and tissue repair. The average adult has about five litres of blood.</p>
<p>The different types of blood cells include red blood cells, platelets, and white blood cells, and these are produced in the bone marrow, in the centre of our bones.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/177639/original/file-20170710-587-zksmvf.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/177639/original/file-20170710-587-zksmvf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/177639/original/file-20170710-587-zksmvf.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=306&fit=crop&dpr=1 600w, https://images.theconversation.com/files/177639/original/file-20170710-587-zksmvf.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=306&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/177639/original/file-20170710-587-zksmvf.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=306&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/177639/original/file-20170710-587-zksmvf.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=384&fit=crop&dpr=1 754w, https://images.theconversation.com/files/177639/original/file-20170710-587-zksmvf.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=384&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/177639/original/file-20170710-587-zksmvf.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=384&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption"></span>
<span class="attribution"><span class="source">The Conversation</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Red blood cells</h2>
<p>Red blood cells are essential for transporting oxygen around the body. Red cells are very small, donut-shaped cells with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3678251/">an average lifespan of 120 days</a> within the body. They contain a protein called haemoglobin, which contains iron and binds very strongly to oxygen, giving blood its red colour. </p>
<p>Red cells are flexible and able to squeeze through even the tiniest of our blood vessels, called capillaries, to deliver oxygen to all of the cells in our body. When the red cells reach our organs and tissues, haemoglobin releases the oxygen.</p>
<h2>Platelets</h2>
<p>Platelets are even smaller than red blood cells. In fact, they are tiny fragments of another much larger type of cell, called a megakaryocyte, which is located in the bone marrow. Platelets are formed by budding off from the megakaryocyte. Platelets have an average lifespan of eight to 10 days within the body, so they are constantly being produced. When body tissue is damaged, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4925965/">chemicals are released that attract</a> platelets. </p>
<p>Platelets clump together and stick to the damaged tissue, which starts to form a clot to stop bleeding. Many of the proteins that help the clot to form are contained in plasma. Platelets also release growth factors that help with tissue healing.</p>
<hr>
<p><a href="https://theconversation.com/from-animal-experiments-to-saving-lives-a-history-of-blood-transfusions-80391"><em>Infographic - From animal experiments to saving lives: a history of blood transfusions</em></a></p>
<hr>
<h2>White blood cells</h2>
<p>Blood also carries white blood cells, which are an essential part of our immune system. Some white cells are able to kill micro-organisms by engulfing and ingesting them. Other types of white cells, called lymphocytes, release antibodies that help to fight infection.</p>
<p>Blood cells don’t act alone; they work together for normal body function. For example, when we cut our skin, platelets help plug the cut to stop it bleeding, plasma delivers nutrients and clotting proteins, white cells help to prevent the cut from becoming infected, and red cells deliver oxygen to help keep the skin tissue healthy.</p>
<h2>Blood transfusions</h2>
<p>Sometimes patients who are having surgery, cancer treatment or when they are seriously injured need a blood transfusion. This is usually because they have lost a lot of platelets, red cells or plasma, or because their cancer treatment has killed many of their blood cells.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/5ZMuPciBVy8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">The journey of blood.</span></figcaption>
</figure>
<p>In Australia, blood is donated by voluntary blood donors at the <a href="http://www.donateblood.com.au/">Australian Red Cross Blood Service</a>. A typical whole blood donation is just over 450 mL, and it takes around ten minutes to collect. Every time a donation is made, the donor is screened for infectious diseases such as hepatitis and HIV, so these aren’t transferred to the patient receiving the blood. </p>
<p>After donation, the blood is separated into its different parts: platelets, red cells and plasma, which are known as blood components. White cells are removed because they can cause problems in patients who receive them. Once the blood has been separated, it’s stored until it’s needed by hospitals. The red blood cells are stored in a refrigerator and the plasma is frozen. The red cells can be stored for six weeks, and the plasma can be stored for up to a year. Platelets can only be stored for five days. When a hospital needs blood it’s packed into special blood shippers, and transported to the hospital blood bank to be transfused.</p>
<hr>
<p><em><strong>Read other articles in the series:</strong></em></p>
<p><em><a href="https://theconversation.com/essays-on-blood-why-do-we-actually-have-it-75064">Essays on blood: why do we actually have it?</a></em></p>
<p><em><a href="http://theconversation.com/from-animal-experiments-to-saving-lives-a-history-of-blood-transfusions-80391">From animal experiments to saving lives: a history of blood transfusions</a></em></p><img src="https://counter.theconversation.com/content/75066/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Denese Marks receives funding from the Australian and New Zealand Society of Blood Transfusion, Defence Health Foundation and MacoPharma Pty Ltd. Australian governments fund the Australian Red Cross Blood Service for the provision of blood, blood products and services to the Australian community.</span></em></p>Blood transports nutrients, hormones, proteins, vitamins and minerals around our body.Denese Marks, Adjunct Associate Professor, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/803912017-07-24T20:11:59Z2017-07-24T20:11:59ZFrom animal experiments to saving lives: a history of blood transfusions<figure><img src="https://images.theconversation.com/files/177035/original/file-20170706-25573-1swznwp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Blood transfusions save lives - at least they do now. Here's how an ancient experiment became a routine life saver. </span> <span class="attribution"><span class="source">from www.shutterstock.com.au</span></span></figcaption></figure><p><em>This week we’re running a series in collaboration with the Australian Red Cross Blood Service looking at blood: what it actually does, why we need it, and what happens when something goes wrong with the fluid that gives us life. Here we look at how blood transfusions started as an experiment four centuries ago, and became a modern-day life saver. Read other articles in the series <a href="https://theconversation.com/au/topics/blood-series-39533">here</a>.</em></p>
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<img alt="" src="https://images.theconversation.com/files/179381/original/file-20170724-11666-1vw5mhn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/179381/original/file-20170724-11666-1vw5mhn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=2916&fit=crop&dpr=1 600w, https://images.theconversation.com/files/179381/original/file-20170724-11666-1vw5mhn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=2916&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/179381/original/file-20170724-11666-1vw5mhn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=2916&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/179381/original/file-20170724-11666-1vw5mhn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=3664&fit=crop&dpr=1 754w, https://images.theconversation.com/files/179381/original/file-20170724-11666-1vw5mhn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=3664&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/179381/original/file-20170724-11666-1vw5mhn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=3664&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="attribution"><span class="source">The Conversation / Australian Red Cross Blood Service</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p><em><strong>Read other articles in the series:</strong></em></p>
<p><em><a href="https://theconversation.com/essays-on-blood-why-do-we-actually-have-it-75064">Essays on blood: why do we actually have it?</a></em></p>
<p><em><a href="http://theconversation.com/explainer-whats-actually-in-our-blood-75066">Explainer: what’s actually in our blood?</a></em></p><img src="https://counter.theconversation.com/content/80391/count.gif" alt="The Conversation" width="1" height="1" />
Here we look at how blood transfusions started as an experiment four centuries ago, and became the modern-day life saver they are.Alexandra Hansen, Deputy Editor and Chief of Staff, The Conversation AUNZEmil Jeyaratnam, Data + Interactives Editor, The ConversationSteven Phillips, Multimedia EditorLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/750642017-07-23T20:10:04Z2017-07-23T20:10:04ZEssays on blood: why do we actually have it?<figure><img src="https://images.theconversation.com/files/178776/original/file-20170719-13561-1ibysp7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">We know blood is vital for life, do we know why?</span> <span class="attribution"><span class="source">Illuminations: Blood Equality by Jordan Eagles (USA) Image credit: David Meanix and courtesy of artist as part of Science Gallery Melbourne’s BLOOD exhibition</span></span></figcaption></figure><p><em>This week we’re running a series in collaboration with the Australian Red Cross Blood Service looking at blood: what it actually does, why we need it, and what happens when something goes wrong with the fluid that gives us life. Read other articles in the series <a href="https://theconversation.com/au/topics/blood-series-39533">here</a>.</em></p>
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<p>Just as a village can’t grow into a city without some form of transport (road, rail or river) that provides necessary interconnections for it to flourish, living things are limited in the size they can reach unless they have some form of circulatory system to transport nutrients and remove waste.</p>
<p>Single celled organisms such as bacteria and fungi, and some multicellular creatures such as sponges, corals and flatworms, simply absorb the nutrients they need and get rid of their waste using a passive process known as diffusion (which is much like soaking in and draining out).</p>
<p>More complex animals have developed some kind of circulatory system. A variety of different systems and pumps (hearts) have developed, but they all have a few things in common. These include something to carry oxygen around their bodies, a fluid of some sort, and some “plumbing” – in humans (and a number of other species) the fluid is called blood and the plumbing is our arteries, veins and capillaries. The oxygen carrier is haemoglobin.</p>
<p>Depending on the organism and where it has adapted to live, its oxygen carrier can come in different forms, often giving its “blood” different colours. Spiders, crustaceans, octopuses and squid use haemocyanin, which is based on copper and gives them blue blood. This carrier works well in low oxygen environments and in the cold. </p>
<p>Segmented worms and some leeches use an iron based carrier called chlorocruorin, which can appear either green or red, depending on its chemical environment. Vertebrates, including humans, use haemoglobin, which makes their blood red.</p>
<p>A truly special case is the <a href="https://blogs.scientificamerican.com/brainwaves/how-the-antarctic-icefish-lost-its-red-blood-cells-but-survived-anyway/">Antarctic icefish</a>, which lost its haemoglobin long ago as a result of a presumably random mutation. It has adapted though, and now survives by transporting oxygen that is simply dissolved in its blood. This is possible thanks to the cold conditions it lives in.</p>
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<a href="https://images.theconversation.com/files/176694/original/file-20170704-7743-1u6unbb.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/176694/original/file-20170704-7743-1u6unbb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/176694/original/file-20170704-7743-1u6unbb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=419&fit=crop&dpr=1 600w, https://images.theconversation.com/files/176694/original/file-20170704-7743-1u6unbb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=419&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/176694/original/file-20170704-7743-1u6unbb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=419&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/176694/original/file-20170704-7743-1u6unbb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=526&fit=crop&dpr=1 754w, https://images.theconversation.com/files/176694/original/file-20170704-7743-1u6unbb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=526&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/176694/original/file-20170704-7743-1u6unbb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=526&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<h2>What is our blood made of?</h2>
<p>Human blood, and that of all creatures with backbones (Antarctic ice fish excepted), is red. The colour comes from a chemical known as haem, which contains iron. It’s the iron that is the crucial ingredient for carrying oxygen. Oxygen is needed for our cells to burn sugars, fats and proteins in a controlled way. This provides us with the energy we need to live.</p>
<p>Outside our bodies, we know that when iron is exposed to oxygen, it rusts. And it doesn’t easily “unrust”. But to work as an oxygen carrier in our bodies, iron needs to “rust” and “unrust” on demand - picking up oxygen where it is in plentiful supply (our lungs), and releasing it where it is required (the cells in our organs).</p>
<p>This on/off oxygen switch is made possible with help from complex larger molecules. The first is haem, a flat ring structure that holds an iron atom at its centre. Haem is held closely by proteins known as globin, and this combination forms haemoglobin, which is itself packaged up in red blood cells to be transported around the body.</p>
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<p><a href="https://theconversation.com/from-animal-experiments-to-saving-lives-a-history-of-blood-transfusions-80391"><em>Infographic - From animal experiments to saving lives: a history of blood transfusions</em></a></p>
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<p>The molecular structure of haemoglobin is delicately tuned to allow it to bind oxygen in the lungs and drop it off in areas where there is less oxygen available.</p>
<p>Red cells are specialised parcels, lacking DNA, that are able to squeeze through the tiniest capillaries, down to four millionths of a meter (equivalent to roughly half their diameter). Their donut shape maximises their surface area to make sure they can efficiently deliver oxygen, while keeping them small enough to fit through the smallest blood vessels.</p>
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<a href="https://images.theconversation.com/files/176861/original/file-20170705-4592-1q4j491.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/176861/original/file-20170705-4592-1q4j491.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/176861/original/file-20170705-4592-1q4j491.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=286&fit=crop&dpr=1 600w, https://images.theconversation.com/files/176861/original/file-20170705-4592-1q4j491.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=286&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/176861/original/file-20170705-4592-1q4j491.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=286&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/176861/original/file-20170705-4592-1q4j491.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=360&fit=crop&dpr=1 754w, https://images.theconversation.com/files/176861/original/file-20170705-4592-1q4j491.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=360&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/176861/original/file-20170705-4592-1q4j491.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=360&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The Antarctic ice fish managed to evolve past needing red blood cells and instead absorbs oxygen.</span>
<span class="attribution"><span class="source">Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
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<h2>More than just the red stuff</h2>
<p>As well as red cells, our blood contains other cells and chemicals that repair and maintain the transport system and send signals around the body.</p>
<p>White blood cells, also known as leukocytes, repel or destroy invaders. Some white blood cells (lymphocytes) manufacture molecules known as antibodies that tag viruses and bacteria for destruction, while others called neutrophils and macrophages (literally “big eaters”) engulf bacteria, fungi and parasites to keep our circulation clean. When neutrophils have done their job you sometimes might see them as the main component of pus.</p>
<p>Platelets are very small fragments of larger cells called megakaryocytes. They react to any breaches to the walls of blood vessels, gathering together and triggering reactions that form a plug (or a clot) for the damaged section. If a person doesn’t have enough platelets, they can suffer from uncontrollable bleeding.</p>
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<span class="attribution"><span class="source">The Conversation</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<h2>Where does it come from?</h2>
<p>All blood cells (red cells, white cells and platelets) develop from haematopoietic (literally meaning “blood-making”) stem cells, located in the bone marrow. It has recently been found that many <a href="https://www.ncbi.nlm.nih.gov/pubmed/28329764">platelets are made in the lungs</a>, from megakaryocytes that have migrated there from the bone marrow.</p>
<p>As stem cells develop, they progressively specialise into the many different types of blood cells, making developmental choices along the way. The specialisation of cells during development is tightly controlled by a symphony of growth factors. In some types of blood cancers and serious diseases, stem cell or bone marrow transplants can be used to “reboot” the blood making system.</p>
<p>As our knowledge of the control of blood cell development grows, we’re making progress towards being able to <a href="https://www.newscientist.com/article/2131517-human-blood-stem-cells-grown-in-the-lab-for-the-first-time/">reproduce this process in cells grown in the laboratory</a>. This is still some time away from being a broadly available process, but an exciting area to watch as it develops.</p>
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<p><em>Update: the sentence outlining the shape of red blood cells was incorrect and has been reworded.</em></p><img src="https://counter.theconversation.com/content/75064/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Irving is employed by the Australian Red Cross Blood Service and has research collaborations with others receiving NHMRC and ARC research grants.
Australian governments fund the Australian Red Cross Blood Service for the provision of blood, blood products and services to the Australian community.</span></em></p>Everything you never knew about the red stuff in your veins.David Irving, Adjunct Professor, University of Technology SydneyLicensed as Creative Commons – attribution, no derivatives.