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TRANSPLANTS
& TRANSFUSION

Everything
You Want To
Know About

platelets

Courtesy of South Texas Blood & Tissue Center

So what are platelets? You also can donate just platelets using a process called apheresis.
Platelets are one of the major components of your blood. When Your blood goes through a machine that separates the platelets and
returns the rest of the components to your body. This produces one
they’re sailing around your bloodstream, platelets look like little to three units large enough to affect an adult patient’s platelet count.
saucers — sort of streamlined little brothers of red blood cells.
Why should i donate platelets?
When there’s a break in a blood vessel, platelets become “acti- Essentially, two reasons.
vated.” Activated platelets look like aliens from a 1950s sci-fi movie. First, they’re in high demand, especially for cancer patients. Sec-
They’re full of what appear to be tentacles, which help them bind to-
gether and encourage other blood-clotting components to join in, in ond, they have a short shelf life, typically five days or less. The prob-
most cases plugging an opening in an artery or vein. lem is that they become sticky very easily, so they can’t be refrigerated
and they have to be agitated constantly.
Platelets were first described by the British scientist George Gul-
liver in 1841, observed under one of the earliest microscopes. Other blood components can be refrigerated and/or stored frozen
for longer periods of time. But not platelets.
Who needs platelets?
People who have traumatic injuries need platelets beyond what how long does it take to donate platelets?
An average donation takes about two hours, or the length of “The
their bodies can produce. People who are undergoing cancer treat-
ments need platelets, because the treatments can reduce the amount Dark Knight.”
of platelets their bodies produce. And people who are receiving trans-
plants often need them as well. how often can i donate platelets?
You can donate about every seven to 10 days, up to 24 times in a
how do you collect platelets?
There are two typical ways to collect platelets. year.
If you donate whole blood, after your donation is done, we use a
What are the requirements?
system that separates the platelets from the red blood cells and the You have to be at least 17 years old, weigh at least 110 pounds and
plasma, the liquid that carries the platelets and red cells through the
bloodstream. To make a unit large enough to raise an adult’s platelet be in good health. Also, your body needs to have a certain platelet
count, we need to combine four to six of these separate donations. count — which we’ll measure — to see if you are able to donate.

14 San Antonio Medicine • April 2016