How many platelets in a donation?

September 23, 2023 6:25 PM

How many platelets are there in a typical donation? Can they be counted, or is it just a volume measurement like 300mL?

I donated platelets on Friday. Yay, me!

The machine had a number on its display that counted up steadily, like "10.3 x 10^something." (The guy across the way was counting up to like 7.9. I crushed him!)

Was that number a count of platelet cells?

posted by wenestvedt to Science & Nature (3 answers total)

Normal circulation platelet count is 150-450 billion [average=3x10¹¹] / litre. For platelet donation, they hook you up to a centrifuge which preferentially spins out platelets, the smallest solid components, returning the rest to the donor. A typical donation is 2x 'units' of platelets, which I gather is the amount which would normally be present in 1 litre = 6x10¹¹ platelets; you and the other bloke have given above and beyond, so hats off!! They'll welcome you back for more in 28 days.
posted by BobTheScientist at 12:28 AM on September 24, 2023 [1 favorite]

US FDA platelet donation regulations, with frequency of donation
posted by Iris Gambol at 3:09 PM on September 24, 2023

Response by poster: Thanks, IrisG! That page says, in part:

Sec. 640.24 Processing.
...
(c) The time and speed of centrifugation must have been demonstrated to produce an unclumped product, without visible hemolysis, that yields a count of not less than 5.5 * 10^10 platelets per unit in at least 75 percent of the units tested.

So assuming that I gave a double product, that would be 106,000,000,000 platelets by the time I finished.

(I'm just imagining counting them out like glass beads on a mandala board, and it taking forever....)
posted by wenestvedt at 6:03 AM on September 25, 2023 [1 favorite]