Whole Blood & Platelets: What’s the Difference?

July 28, 2011 at 11:01 am

By Julie Ruel, Social Media Manager, Stanford Blood Center

At Stanford Blood Center we collect several different types of blood products from our volunteer donors. All products have different functions pre- and post-donation. In other words, before and after they leave your body, they each serve different purposes. For the scope of this article, I’ll focus on red blood cells (RBCs) collected during a whole blood donation and platelets collected during an ABC donation. These are the two most common products we draw, accounting for about 99% of our total donations in a year.

During a whole blood donation, a unit of RBCs is collected. These cells are packed full of hemoglobin and have an important job during their short life inside us (about 120 days). They work diligently around the clock to carry oxygen through arteries to our organs and tissues. Then, via the veins, they return, de-oxygenated, to the heart and lungs.

After we draw the unit, it’s sent to our lab for testing, then shipped off to the local hospitals we serve. RBCs are used, for example, for accident victims and those undergoing surgery and are required for about 70% of all transfusions.

It takes about eight weeks for these iron-rich cells to replenish themselves, which is why donors are required to wait 56 days between donations. Most don’t feel any side effects from the donation, though it does take about 24 hours for the fluid loss to be replaced. Because of this, we ask that donors refrain from strenuous exercise during that period.

Platelets have a different, and still very important function. Because of them, when we bleed, our blood clots. When we draw platelets from donors, they are sent through the same gamut of tests as RBCs, then shipped to the hospitals to use for patients who may not have enough of them to control their bleeding. Patients undergoing treatment for cancer are the primary users of platelets.

Because such a small, insignificant number of RBCs (that, as you remember, carry oxygen to our organs) are lost during a platelet donation, donors feel little, if any, fatigue afterwards. Platelets regenerate quickly and can be donated every 72 hours, up to 24 times in a year.

We welcome all who meet the requirements for donating whole blood to make an appointment at a Center location or blood drive. For example, donors must:

• weigh 110 pounds or more

• be at least 17 years of age (16 with parental consent)

• be feeling well with no symptoms of colds, flu or infection

Platelet donation eligibility is the same as whole blood with a few additional requirements. We screen each donor for the antibody to the cytomegalovirus and typically only draw platelets from those who test negative. In addition, at least one prior whole blood donation must be made at SBC in order to determine eligibility. For more specifics, please visit our website.