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Comment by aueightyfive | Hacker News Reader

Another great reason to become a regular blood donor. I recall reading that the only way to remove these forever substances from your blood was through donations. My wife and I go every 3 months.

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For anyone else interested in reading more: https://jamanetwork.com/journals/jamanetworkopen/fullarticle...

Who would have thought bloodletting[1] would make a comeback.

[1] https://en.wikipedia.org/wiki/Bloodletting

I was surprised to learn that a full blood donation (500ml) is about 10% of all of the blood in the body.

I was surprised that you cannot donate less than a pint of blood. I wanted to donate but that put me off, one pint is too much lost blood in one sitting. I wonder why these restrictions and why not allow people to donate half of that for example. Is it just for convenience for blood collectors?

> I wanted to donate but that put me off, one pint is too much lost blood in one sitting.

What do you mean?

Off the top of my head, I imagine blood bag sizes are standardized, so they're easy to deal with during an emergency transfusion.

It would be a nightmare to deal with containers with mixed volumes of blood. "This patient needs 3 litres of O-, let me figure out which combination of blood bags do I need now"

Donated blood is not used directly like that.

It is indeed tested and mixed.

That's why they ask so many questions about your risk of disease when donating.

I didn't know it was mixed, thanks for the clarification. I guess it makes sense to mix it.

It's because blood bags are typically pre-filled with a measured dose of an anticoagulant to increase how long the blood can be stored. If they're only partially filled there will be too much anticoagulant for the volume of blood.

I believe the most common anticoagulant used today is Citrate Phosphate Dextrose Adenine Solution (CPDA-1), which doesn't have a Wikipedia page, but it's mentioned on the page for the the older acid-citrate-dextrose:

https://en.wikipedia.org/wiki/Acid-citrate-dextrose

However, I agree that volumes of blood per donation (which varies by country) are sometimes so big that it probably discourages many potential donors. It's possible that demanding such a large quantity from each donor reduces the total amount of blood donated.

You do you, but I'm pretty athletic, donate blood frequently, and have never really noticed any degradation in my athletic performance the day after a donation. Unless you have some medical condition, the standard amount is no big deal.

So the solution is to give it to someone else?

the recipients have bigger problems than PFAS, so it is a win-win deal

The sollution to pollution is dilution. (half joking)

If you go regularly the concentration of PFAS in your donated blood would be lower compared to going more sporadically.