Generally, the guideline is don’t donate more frequently than once every two months, but suppose there were some truly dire emergency that required as much blood as possible, could someone donate just one month or even 2-3 weeks after having just donated?
Could they? Sure. Whether it would cause health issues or not is another question, but I know the American Red Cross will not, under any circumstances, let a registered blood donor donate more frequently than every 2 months. How do I know? I tried doing it this year, just a few days short of the 59 required days between donations and I was flatly refused. You can try donating under an assumed name, but I can’t really envision an emergency that would require a person to donate that frequently anyway…
It’s 8 weeks / 56 days between donations, not 59. The blood drive coordinator where I work (a college with hundreds of staff and 10K+ students) has drives scheduled exactly every 8 weeks.
From the Red Cross FAQ
How long will it take to replenish the pint of blood I donate?
The plasma from your donation is replaced within about 24 hours. Red cells need about four to six weeks for complete replacement. That’s why at least eight weeks are required between whole blood donations.
You must wait at least eight weeks (56 days) between donations of whole blood and 16 weeks (112 days) between Power Red donations. Platelet apheresis donors may give every 7 days up to 24 times per year. Regulations are different for those giving blood for themselves (autologous donors).
Canadian regulations are a bit stricter:
You can donate:
Whole blood every 56 days for males, every 84 days for females.
Plasma every seven days.
Platelets every 14 days.
I used to work with a guy who said his mom donated so much blood during WWII she became permanently anemic. It’s not a good idea to donate more than the recommended schedule.
Interesting!
Are minors allowed to donate? In the U.S., you can at 16 with parental permission.
NHS rules are:
You can give blood if you:
are fit and healthy
weigh between 7 stone 12 lbs and 25 stone, or 50kg and 160kg (110lbs and 350lbs)
are aged between 17 and 66 (or 70 if you have given blood before)
are over 70 and have given blood in the last two years
Men can give blood every 12 weeks and women can give blood every 16 weeks.
So how does that work exactly?
Does that mean that even if she ate lots of iron, it just wasn’t attaching to her blood?
Right, but I’m not so much asking about rules/regulations as I am asking what the true physical limits are. Where is the boundary between unadvisable and dangerous?
I know that, in the early stages of treatment for hemochromatosis (basically, high blood iron), I was giving a unit of blood every week. That suggests that iron is the limiting factor, and that giving more frequently than the regulations say won’t result in problems other than the iron.
I don’t know how quickly you can get iron into a normal, non-hemochromatotic human, though. And even in the case of hemchromatosis, that’s drawing down levels that accumulated over the course of decades.
There is an alternative to donating whole blood, if you want to benefit the blood supply. Donate platelets. In the US you can donate platelets twice a month I believe. I tried donating platelets but the needle size is different, and for me it kept clogging up. But my BIL is a regular platelet donor.
In Australia there was this guy, who becuase of age restrictions has had to retire from donating.
If your body takes 4-6 weeks to make the new red blood cells, though, won’t you eventually start running low on red blood cells if you donate too often?
Although…maybe the human body accelerates replacement of red blood cells when it senses that it’s lost a lot of blood of late?
I think the point is that the limiting factor on the production of red blood cells is the iron supply. Since (at the time) my body had a surplus of iron, it was able to make new red blood cells very quickly (until that surplus was drawn down).
Answers to the 2 questions above, from my experiences as a frequent blood donor and then running low on red blood cells/iron: Yes and no
I donated 3 times this year, January, March and May. When I tried donating in July my iron levels were too low. This also happened to me around 10 years ago and both the blood center staff and my own doctors have told me to hold off on donating for several months or even a year and to take iron supplements.
Only about 10% of the iron ingested by most people is absorbed, regardless of its source. However, some people who are not only severely anemic but also have inadequate iron stores can receive a gram or more of iron intravenously. There are several preparations in use.
It sure does. Everyone has a few reticulocytes (immature RBCs) circulating, but if they experienced a serious bleeding episode or are anemic, that number will increase. They do work, just not as well.
Once a month? My Grandfather was donating every 2 weeks in WWII, and he didn’t think that was unusual.
Is that the maximum limit at which the human body can regenerate lost red blood cells (if a pint of blood bi-weekly?)
Here’s just one source. I do know that gradual blood loss (i.e. a slow GI bleed or large menstrual losses) is more dangerous than a large hemorrhage.
It depends on how big you are (how much blood you have to start with). 1 pint every two weeks is a fit person of average size. I suppose there is also some variation in how fast you can recover, but that isn’t related to size: a typical mouse takes about two weeks to recover from a mouse-sized extraction. There are other problems with smaller more frequent extractions, but I don’t know what they are.
There are two things going on: 1 pint is about as much as you want to loose at any one time ever (and that already is too much for some people, who do half pint donations). It takes a day or two just to recover from the shock of loosing so much blood. Then it takes 2 weeks to replace the red blood cells. Then – what – I suppose they give you a couple of months to recover from the effort of replacing the blood cells, and to be sure that nothing else goes wrong??