BrainStuff Classics: What Happens to Donated Blood?

After you donate blood, it goes through a complex system of testing, processing, and storage before it can be delivered to patients who need it. Learn how the system works in this classic episode of BrainStuff.

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Episode Transcript

Speaker 1 (00:01):
Welcome to brainstud a production of iHeartRadio.

Speaker 2 (00:06):
Hey brain Stuff, I'm Lauren vogel Bomb, and this is
a classic episode from our archives. This one goes into
the complex system that medical care providers use to make
sure that donated blood is safe from source to infusion.
Hey brain Stuff, Lauren Vogel Bomb. Here.

Speaker 1 (00:26):
This episode talks about blood donation. So if that's the
kind of thing that makes you woozy, go on and
skip it. Okay, Every two seconds in the United States,
someone somewhere needs a blood transfusion. And let's face it,
many of us don't consider giving blood until there's a
major disaster where donations are needed. But just one donation
has the potential to save up to three lives on average.

(00:49):
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

(01:09):
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

(01:31):
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

(01:53):
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

(02:14):
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

(02:36):
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

(02:57):
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

(03:19):
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

(03:41):
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.

(04:02):
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

(04:24):
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.

Speaker 2 (04:54):
Today's episode is based on the article what Happens to
Blood Once You Donate It on housetiff works dot com,
written by Shelley Dancy. Brain Stuff is production of by
Heart Radio in partnership with how stuffworks dot com, and
it's produced by Tyler Klang. Four more podcasts my heart Radio,
visit the iHeartRadio app, Apple Podcasts, or wherever you listen
to your favorite shows.