BrainStuff Classics: What Happens to Donated Blood?

When you donate blood, you provide about one pint. That's about half a liter of whole blood, which is called a unit of blood, and for reference, that's about sixteen ounces, or the size of a large coffee. But in the US alone, there is a need for almost thirty six thousand units of blood every day, so it's excellent for those who can donate to do so. But have you ever wondered what actually happens after your blood is drawn for a donation, Where does it go and how is

the process tracked for safety and security. We'll break it down. Step one is collection. When you donate blood, it's collected in a special bag and likely a few test tubes that were developed with an antiquagulant to prevent the blood from clotting. Each bag and test tube is assigned the same unique ID number to ensure that the collected blood can be properly tracked and eventually labeled. Then the blood is placed on ice before it's sent to the lab

for testing. Next, the bags and test tubes of blood are packaged in boxes specially made to keep blood at the right temperature until it can reach laboratories. For step two processing, the test tube samples are sent off to the lab for testing to be sure the blood is safe and to determine the blood type. In the US, the FDA regulates blood testing, clatlection, and blood components through

its Center for Biologics, Evaluation and Research. While that blood is being tested, a blood processing center verifies the receipt of the whole blood, sort of like tracking a package from post office through delivery. The blood's idea is checked in at every step of the way. Next, the units of whole blood are separated into specific components. This separation process, which is called component therapy, is accomplished by spinning the

blood in a centrifuge. The heavy red cells fall to the bottom and the blood is divided into transfusible components red cells, platelets, and plasma. The plasma might even be processed further. For instance, plasma can be separated into cryoprecipitate called cryo for short, which helps control the risk of bleeding by helping blood to clot. The red blood cells, plasma, and platelets are then heat sealed in bags to ensure they remain sterile, and the components are stored while they

wait for their test results. Plasma and cryo contain proteins that are pretty stable, so they can be frozen for up to time a year at negative twenty seven degrees fahrenheit that's negative thirty three celsius. Red cells are more delicate and have to be refrigerated, but can be kept for up to forty two days as long as they're held at forty two degrees fahrenheit that's six degrees celsius.

Platelets must be used within five days and are stored at room temperature in agitators that rock them back and forth until they are transfused into a patient. Through all of this, the blood processing center is still tracking the donation, including manufacturing data, what centrifuge was used to separate the blood, and what time the work was performed. Once they get an okay on the blood tests from the lab, the

components are ready to be deployed. They print labels with information including the blood type and expiration dates, which they then affix to the bags. If the blood is deemed unsafe during the testing, it's tagged with a discard label to complete the tracking cycle. When a hospital or treatment center places an order for blood or plasma, the components

are shipped off in temperature safe boxes. When they arrive, the medical staff double checks them for safety, and finally they're ready to be transfused into the patient who needs them. The entire donation to shipping process can take up to three days, which doesn't seem like a long time until there's a major disaster or blood shortage. The American Red Cross says blood supply usually can't keep up with demand because only about three percent of people eligible to donate

actually do. That's why it's such a boon to donate if you can, especially if you're a universal donor with type O negative blood. This can be transfused into any

patient with any blood type. The American Red Cross estimates that about forty five percent of people in the US have type OH blood, but the overwhelming majority of those people are OH positive, which is lucky for them because it means that donated components are more likely to match their common type, but it also means that just seven percent of people are type O negative that universal donor.