How many more blood donations would it take in the United States per year to end blood shortages?

June 23, 2011 12:13 AM

How many more blood donations would it take in the United States per year to end blood shortages?

Suppose, if you will, that you could snap your fingers and cause n additional donation events per year. What would n be? 10K donations? 100K donations? 1M? How much would be necessary, to fulfill all reasonable needs?

I understand that not all blood is equally valuable, so feel free to break things down. I also understand that not all blood donations are accepted, but don't know the rejection rate. Finally, I'm interested in international numbers too, but specifically looking for donation requirements across US (though -- are things just as bad overseas?).

posted by effugas to health & fitness (8 answers total)

A starting point: "More than 38,000 blood donations are needed every day."
posted by vidur at 12:21 AM on June 23, 2011

38,000 donations a day. Hmm. That'd be 13.8M units a year. But later:

"The number of blood donations collected in the U.S. in a year: 16 million (2006)."

That seems independent of how many units are used per patient (which can be quite a bit, of course).

Still, great link!
posted by effugas at 12:47 AM on June 23, 2011

Don't forget that in addition to the donations actually used for patients, there's also a certain amount used for research, plus some wastage: blood doesn't last too long, even refrigerated, and some is always thrown out. But, since the blood products MUST be available immediately when and where its needed, you can't simply reduce the total number of donations by the amount wasted: there HAS to be a supply on hand at all times.

As for the number of prospective donors needed to maintain that minimum on-hand supply: I'm no expert, but each time I've organized blood drives, we were required to have a minimum of 40 prospective donors pre-signed, from which the bloodmobile people said they expected to actually get about 32 actual pints of blood donated.
posted by easily confused at 3:17 AM on June 23, 2011

Another relevant issue is that not all blood is equally useful to all patients. People who get lots of transfusions tend to develop antibodies to various antigens (proteins) that can be present in blood, effectively making them allergic to some kinds of donor blood. So next time that person needs a transfusion, their health care team needs to find a donor pint that doesn't have those antigens that will cause an allergic reaction. Once a person develops antibodies to several common antigens, it can be really difficult to find blood that will work for them. The more donors giving blood, the more likely it will be to have blood available that is free of whatever combination of antigens a patient is allergic to.
posted by vytae at 6:08 AM on June 23, 2011

I tend to hear about blood shortages more often after disasters than other times -- our need for blood isn't static, so the amount we'd need to prevent any shortages ever is likely very, very high.
posted by toomuchpete at 6:51 AM on June 23, 2011

I'm not sure about the citation here, but the wikipedia article on artificial blood says
"Donations are increasing by about 2-3% annually in the United States, but demand is climbing by between 6-8% as an aging population requires more operations that often involve blood transfusion."
posted by nat at 8:00 AM on June 23, 2011

They can get all the blood they want if/when they start compensating people fairly for it.
posted by eas98 at 1:11 PM on June 23, 2011

I work at a blood bank in recruitment, although I don't deal much with inventory.
Here are a few things to keep in mind:

- Blood has a short shelf life. Red blood cells last for 42 days; platelets last just 5 days. What we need is more consistent donations.

- There is a deferral period between donations so that the donor stays healthy. For whole blood it's 56 days (8 weeks), and for platelet apheresis it's 14 days. So if everyone in the world gave on one day, we'd be screwed because their blood would all expire before it could be replenished.

- Need fluctuates and is unpredictable.

- Collections don't always match needs. Our organization always seems to have too many A+ red cells, for instance. Most blood banks try to export excess collections to other organizations, but yes some does expire.

- toomuchpete: That's more confirmation bias than anything. Our blood bank actually had to turn people away after September 11th (and we're no where near NYC). People feel compelled to give after disasters or other traumatic events, but we usually get too many donors.

- eas98: The reason why the FDA forbids blood banks to pay donors (or give out high-value prizes) is the fear that donors will lie on their intake interviews and it will taint the blood supply. Someone who knows they are HIV+ is going to be much more enticed to lie and donate blood if they get cash for it rather than just a t-shirt.

- Deferral rate is also something to consider, and often is based on how educated the donor population is about blood donations. We do our best to get donors to "pump up their iron" (eat iron-rich foods ahead of time) so that they have a high enough hemoglobin, and we also try to educate them about who can and can not donate blood. I believe our deferral rate is around 20%.

- Another point to consider is that whole blood is rarely transfused. In the lab, your whole blood donation is separated into components - so up to three patients could benefit from your donation (red blood cells, plasma, platelets). There are also different types of donations, including apheresis (automated technology that collects a larger volume of a certain component).

Ok sorry if I just hogged the thread. This is an interesting question, I'm just not sure if there is a hard and fast answer!
posted by radioamy at 2:11 PM on June 23, 2011 [1 favorite]