The Blood Matters Blog ·

What Is a Buffy Coat?

Spun at high speeds, whole blood separates into plasma and red blood cells. But sandwiched between the two is a tiny but very important layer: the buffy coat.

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Centrifugation and the buffy coat layer

Want to know something amazing? If you've ever given whole blood at Our Blood Institute before, you're likely saving even more lives than you know!

That's because of something called a buffy coat. In the world of blood banking and laboratory science, the term "buffy coat" refers to a thin, pale collection of cells that — while small in volume — is packed with powerful components vital to research and a healthy platelet supply.

Collecting the Buffy Coat Layer

After donation, your unit of whole blood is sent to our lab, where it's placed inside a centrifuge and spun at high speed. Through this centrifugation process, your whole blood donation separates into three distinct layers based on density:

  • Plasma rises to the top

  • Red blood cells settle at the bottom

  • The buffy coat layer rests in between

RELATED: Where Your Blood Goes After Donation

What's Contained within the Buffy Coat

This layer typically accounts for less than 1% of the total blood volume, but it contains a highly concentrated mixture of leukocytes (white blood cells) and thrombocytes (platelets).

Wait, Why Is It Called 'Buffy Coat'?

Nope, it isn't named after Buffy the Vampire Slayer, although with its infection-fighting ability, there are certainly some similarities. And while mighty, the term "buff" isn't some clever Muscle Beach allusion, either. The name actually comes from its light tan color, which can be described as — you guessed it — buff.

How We Use Buffy Coats to Save Lives

Here at OBI, we are committed to getting the most out of your blood donation, but no single buffy coat has enough platelets to successfully treat a patient. Fortunately, our lab technicians are able to combine platelets from these isolated buffy coats into one effective transfusion dose. (It takes roughly six donations to do this. It takes a village, as they say!)

This "pooled platelet" process is crucial to supplementing our community's supply of platelets. Without it, cancer, surgery and trauma patients would all be negatively impacted. What's more, OBI's research and development team can utilize buffy coats to produce a nutrient source core to cell therapy, an emerging field with incredible cancer-fighting potential.

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