Blood Donations, Blood Transfusions, and Iron

blood and iron: how to optimize iron levels

In the course of my book Dumping Iron, I discussed blood donations and some of their technicalities, specifically how they lower body iron stores.  In this short article I’ll discuss a few more aspects of blood donations, blood transfusions, and iron.

Transfusion of old, stored blood is harmful

When blood is donated, it is mixed with an anticoagulant and a preservative. The former is to keep the blood from clotting, the latter to preserve its shelf life. Currently, donated blood has an expiration date 42 days (6 weeks) from the day it’s drawn. Most of the blood gets transfused well before its expiration date, but some does not, and gets transfused in the last week of its shelf life and up to the expiration date. This is especially true of less common blood types (B negative, say), for which the supply is lower.

When blood is stored, it ages, essentially decomposes. The red blood cells (RBCs) do not all become decrepit simultaneously, since they have different ages when they are donated. An average RBC lives about 120 days inside the body, before it’s destroyed and replaced with a new one. Hence, when a donor gives blood, the RBCs have a range of ages, from 1 to 120 days. As the blood ages inside its container, some of the RBCs get quite old indeed, well over 120 days, and they decompose (lyse) or otherwise decay.

If a patient is transfused with blood that’s been stored for 6 weeks, bad things can happen.

Red blood cells stored 35 days or more are associated with adverse outcomes in high-risk patients. There’s actually been a ton of research on this topic, but as this study is recent, I’ll just focus on this one.

Clinical trials have shown that longer red blood cell (RBC) storage duration does not worsen outcomes; however, these studies included few RBCs near the end of the 42-day storage limit. We tested the hypothesis that these “oldest” RBCs are associated with adverse outcomes.

The study looked at 28,247 transfused patients given 129,483 units of blood (RBCs, not plasma or platelets). They found that units of blood older than 5 weeks, but not those younger, were associated with adverse events. Odds ratio for mortality with older units of blood was 1.40 in critically ill patients – that means they were 40% more likely to die than those given younger units of blood. There was no extra mortality in those not critically ill, but in older patients there was increased morbidity (sickness) – 22% more likely to become ill.

A recent editorial on this matter concludes that “current maximum storage durations should be carefully reevaluated.” In other words, we’re storing blood too long, and the storage length should probably be no more than 35 days. The problem is that blood shortages are always ongoing, and that would further restrict the blood supply.

Why are old units of blood harmful? The editorial answers that “those that received blood stored for six weeks showed several effects associated with increased harm, including disruption in iron handling, increased extravascular hemolysis, and the formation of circulating non-transferrin-bound iron.”

Old blood cells lyse (similar to exploding) or otherwise decompose, and they release iron into the unit of blood, which when transfused gives the patient a large dose of iron. Some of the cells decompose after transfusion, also releasing iron.

Iron is the reason that transfusion of old blood can harm people.

While this may not seem relevant, if you or a family member need a transfusion, maybe you could inquire about (or insist on) blood that’s younger than 5 weeks old. That might save some agony. Some doctors used to order transfusions of the youngest blood possible in certain cases, though I don’t know how common that practice is any longer.

Should the donation interval be longer?

Currently in the U.S., blood donors can give blood at 56 day (8 week) intervals. In my book, I mentioned that after a blood donation, the blood volume recovers quickly, possibly in 24 hours or less, as the body makes plasma to fill in the volume gap. But replacing the lost RBCs takes longer, hence the waiting period of 8 weeks until the next donation.

A recent study argues that this donation interval should be longer, due to iron requirements.

In conclusion, we provide detailed insights into changes and recovery in iron homeostasis over time until 180 days after blood donation in both regular and new whole blood donors. We conclude that for the vast majority of male donors, the donation interval of 56 days is too short to recover from donation-induced reduction in body iron stores. To stay on the safe side, we propose, as our expert opinion, that ferritin should be kept above 30 mg/L at all times. Based on our observations, this implies a baseline ferritin at each donation of at least 50 mg/L. Furthermore, we propose ferritin as the best parameter to assess personalized donation intervals because it (1) significantly decreases upon blood donation in the present study and (2) has been found to be associated with symptomatic ID in blood donors. Alternatively, and in the absence of point-of-care ferritin platforms, development of ID in donors may be prevented by (1) prolongation of donation intervals to 180 days in all donors as suggested by both the current and the REDS-III study and/or (2) (low) dose iron supplementation.

In a nutshell, they don’t want donors to become iron deficient, a laudable goal.  We know from the data in my book that two donations annually almost guarantee having a ferritin in the desirable, low normal range, so that agrees with the study’s conclusion of 180 days between donations.

However, if someone starts with a ferritin on the high side, say >300, which many people have, it could take a long time to lower it given twice a year donations.

The authors also want donors to have enough time to get their iron stores back to where they were before, the very thing we’re trying to prevent.

My conclusion from this is that, if you are a regular blood donor who donates more than twice a year, you should be cognizant of your current ferritin level, in order to avoid iron deficiency.

A problem with taking the authors’ suggestion to the conclusion of lengthening donation intervals is the same one as with old blood: it would shrink the blood supply, probably even more than a shorter shelf life would. So it seems unlikely to happen.

A large national study of ferritin testing in Canadian blood donors found:

Low-ferritin donors {ferritin <25 µg/L] represented 2.9% of first-time and reactivated (no donation in past 12 months) male donors, 32.2% of first-time and reactivated female donors, 41.6% of repeat male donors, and 65.1% of repeat female donors.

So, repeat donors were much more likely to have low ferritin, and especially the women. The study concluded:

The minimum hemoglobin level will be increased to 130 g/L for male donors [13 g/dl, that’s still a low number for men, below normal] and the minimum interdonation interval changed to 84 days (four donations yearly) for female donors based on iron deficiency risk groups.

If I’m reading that right, Canadian women can now donate only 4 times a year, instead of the previous 6 times. It also seems possible that many of the low-ferritin male donors would be found in the low hemoglobin group.

Previously, a minimum hemoglobin of 12.5 g/dl was required for both male and female donors, but just this past year, the American Red Cross raised the minimum for men to 13 g/dl. That should greatly ameliorate the problem of frequent male donors with iron deficiency. (I was also happy to see this statement from the Red Cross, “The Red Cross does not measure iron levels before blood donation. You can have a normal hemoglobin level and be accepted for blood donation, but still have a low iron level. The fingerstick that is done during your health history is a measure of your hemoglobin level.”)

Recovery of hemoglobin after donation

How long does it actually take to recover the RBCs, together with their hemoglobin, after a blood donation?  Some researchers took a look at that.

RESULTS: After donation of approximately 550 mL of whole blood, [Note: larger than the American donation of 450 ml] the lost amount of tHb of 75 ± 15 g (8.8 ± 1.9%) was recovered after a mean of 36 ± 11 days (range, 20-59 days).

CONCLUSIONS: The results of this study confirm the minimal, recommended donation intervals (56 days for men) as adequate when, for the first time, judged upon by tHb as a direct marker of hematologic recovery.

The following chart shows the percentage of subjects, all of them men, average age 30, by how long it took each one to recover all lost hemoglobin after a donation.

About one fourth of them recovered completely in less than 25 days, and half by 35 days. Almost all recovered by just about the time until they could donate again, 56 days.

The human body makes 200 billion red blood cells daily – that’s 2.3 million per second, requiring 2 x 10^15 iron atoms each second. Unfathomable really. But that process speeds up after blood donation. If someone really needs to, and they have adequate iron stores, the body can ramp up production of blood up to 8-fold.

PS: Check out my books, Dumping Iron, Muscle Up, and Stop the Clock.

PPS: Check out my Supplements Buying Guide for Men.


Leave a Comment:

Doug says February 4, 2017

I did a double red blood cell donation a week ago today. No worries about my iron stores, because I have hereditary hemochromatosis and need to keep ahead of it. I think my hemoglobin was 16. When I was diagnosed they took a pint of blood out of me every week for 12 consecutive weeks to get my ferritin down from 500 to about 40, and I felt fine. I’m also big (6’4″ with a heavy build), and that helps. Me losing a pint of blood is a different proposition than a 125 pound woman losing the same amount. I’m also O Neg so every time I’m eligible to donate they start calling and emailing like a crazy ex-girlfriend.

Blood Donations, Blood Transfusions, and Iron says February 5, 2017

[…] post Blood Donations, Blood Transfusions, and Iron appeared first on Rogue Health and […]

Steve Parker, M.D. says February 5, 2017

FYI, I’ve been practicing medicine full-time in the hospital setting in Arizona and I’ve never seen anyone order blood that is “as young as possible.” I don’t deal with emergency trauma, so I’m not familiar with the transfusion practices of trauma surgeons.

    P. D. Mangan says February 5, 2017

    Thanks, Steve. As I recall, it was neonatal transfusions where this took place. I looked and found a reference: “The component supplied (mean unit volume 294 mL) is in SAG-M anticoagulant (see Chapter 3) and has the same specification as that used for neonatal ‘top-up’ transfusions. It should be transfused less than 5 days from donation to reduce the risk of hyperkalaemia.”

José Roberto Sversut says February 5, 2017

Qual nível Hemoglobina e Hematocrito é considerado Anemia?

    P. D. Mangan says February 5, 2017

    The normal range for hemoglobin is: For men, 13.5 to 17.5 g/dl. For women, 12.0 to 15.5 g/dl. That’s according to Mayo Clinic.

Matt says February 5, 2017


Thanks for another great article. I’m not sure if you are still doing a podcast but I would really enjoyt hearing a conversation between you and Joe from He wrote a good piece on iron and having two great minds discuss Iron and how it affects the body would be incredibly interesting.

You guys are two of my favorite researchers/authors and it would be fantastic to hear a back and forth between you. Thanks!


    P. D. Mangan says February 5, 2017

    Thanks, Matt!

Allan Folz says February 5, 2017

Last year, as semi-random luck had it (because I certainly didn’t plan to do this going into it), my wife had a ferritin test 2 days after giving blood and again at 30 days post donation.

Her first result was 12 ng/ml, and her second was 6 ng/ml.

Her hemoglobin wasn’t measured on the first draw, but on the second draw it was 12.5 g/dl.

BTW, if I recall correctly, Am Red Cross checks hematocrit these days, not hemoglobin.

On account of her low number, we decided she should forego a second donation in the fall (our church schedules a blood drive twice a year). I’ve not made up my mind whether I think she should donate again this spring. Arguably if her hematocrit/hemoglobin is OK, she’s good to go… but still.

By way of comparison, my ferritin was 118 ng/ml at 2 days post. I haven’t re-measured, and I did donate a second time in the fall.

I intend to re-measure both our ferritin levels when Life Ext. runs their next 50% off sale.

    P. D. Mangan says February 6, 2017

    Thanks for that Allan. I believe that the ARC may use hematocrit as a back-up, i.e. if you fail the hemoglobin or there’s some kind of other problem, they measure your hematocrit. But it’s been a long time since I’ve donated, so…

Ed Pluchar says February 8, 2017

I have a dumb question: I gave whole blood today. But every single employee tried to get me to donate a double unit on the machine. (Didn’t have time).

Does giving a double unit every 16 weeks achieve the same results, or better, than whole blood every 8 weeks?

Mixing motivations – to help, plus to chelate. Thanks!

    P. D. Mangan says February 8, 2017

    Not a dumb question. The result in terms of dumping iron would be more or less the same as giving whole blood every 8 weeks. It would put you out of action for longer though; for instance, your exercise capacity will be lower for longer than if you gave 1 unit of whole blood. Given adequate iron stores though, my guess is that you recover hemoglobin almost as quickly as for 1 whole blood donation, since the body is capable of ramping up production if necessary, as I wrote in my article.

Michelle says February 9, 2017

At my last scheduled donation, I was deferred because my hemoglobin level was 10.0 (It used to be well over 15). I was encouraged to increase my iron levels and reschedule. In my search to find ways to increase my iron, I found ‘Dumping Iron’ (haven’t actually read it yet, just about it). It’s unnerving to discover that the thing you seek more of may actually be killing you! It was the first time I’d heard of a connection between iron and so many ailments. This issue is new to me; I’m still trying to understand the relationship between hemoglobin and iron. And until today, I’d never heard of ferritin. Am I understanding correctly that I should be safe to increase my iron intake if I continue to donate blood regularly, clearing the excess from my system?

    P. D. Mangan says February 9, 2017

    Hi Michelle. Low hemoglobin like you has can be caused by several things, but the most common reason is iron deficiency. You didn’t state your age, but if you’re under 50, it’s unlikely that you have high iron, and given your hemoglobin, it’s most likely low. As for iron intake, iron supplements should only be taken under a doctor’s advice; blood bank personnel really shouldn’t advise that in my opinion. In addition, iron supplements deliver a large bolus of iron at once, and as I wrote in my book, that can cause DNA damage. My personal preference if I were iron deficient would be to raise my iron without supplements, e.g. by eating red meat – drink some alcohol with it too. (NB: If a doctor tells you to take iron, I’m not saying not to.) Body iron stores only become unsafe as you get into the triple digit levels, 100 or greater, and if you’re iron deficient, that’s unlikely.

      Michelle says February 9, 2017

      Thank you for such a quick reply and the great information! I had a donation appointment this afternoon and was deferred again for low hemoglobin (12.0 – that’s progress!). I am extremely resistant to take supplements of any kind. I’ll keep eating my dark leafy greens and red meat. Someone told me cooking with cast iron should help, so I’ve been doing that too. Oh, and I’m 37. I won’t worry too much at this point about high iron. Thank you again!

Shaq says February 14, 2017

I saw your tweet re: the Malcolm Kendrick blog post about lead. Others have raised the issue in earlier installments, but it’s as if he’s purposefully avoiding the topic. I wonder if he’ll finally do a deeper dive.

    Shaq says February 14, 2017

    Argh. Raised the issue about iron/ferritin….

Don says February 24, 2017

After reading Dumping Iron, I now do regular blood donations. That said, I can’t seem to get my hemoglobin down at all.

My hemoglobin levels at time of donation for the last 4 donations are:

05/06/2016 – 16.8
07/21/2016 – 15.8
12/07/2016 – 17.1
02/20/2017 – 18.0

The last reading was pretty shocking because it had been only 10.5 weeks since my last donation. I eat a lot of red meat, age 45, and live at high altitude (7500 feet), but I figured I was donating often enough that I could at least hold my levels steady.

I take no iron supplements, nor any multi-vitamin that might have iron it.

After the donation on 2/20, I started taking low-dose aspirin and curcumin daily in the hope that will improve the levels. I’ll be donating at the beginning of May.

Any thought’s on my wacky hemoglobin levels?

    P. D. Mangan says February 24, 2017

    Hi Don: Your hemoglobin is not the number of interest, which is ferritin. Barring pathology, hemoglobin is always kept within a fairly narrow range, as yours have. Yours are slightly high, but that can be expected from living at high altitude. To be able to tell how you’re doing with iron, get a ferritin test.

      Don says May 31, 2017

      Finally was able to get a ferritin test, which I had my doctor add to the usual annual checks. Came back as 34. On a side note, my LDL was the lowest I’ve ever seen it, at 100 with an HDL of 66. In the past LDL has been north of 130. Doctor always bitches and wants to put me on statins, which I ignore. However, I was very happy with the result this time. I Have no idea if blood donations influenced my cholesterol, but I don’t feel that my diet and exercise has changed enough over the past year to have changed that so much.

      I’ll probably keep donating until it starts tanking hemoglobin levels. My iron intake should be adequate due to my red meat intake. I feel very comfortable knowing what the ferritin level is at now and will check it annually.

      Thanks Mangan!

Bill says March 31, 2017

PD Today in an online discussion about iron ferritin levels in the blood, a doctor cited this paper as proof that there is no causal relationship between high iron and heart disease.

I have tried to read it but frankly it is too complex for me. I cannot even makea judgemnet about whether it is accurate or not. Could you take a look and demystify it ?

How Blood Donations Deplete Iron - Rogue Health and Fitness says April 14, 2017

[…] I discussed other aspects of blood donation, iron, and transfusion here. […]

John says January 3, 2019

Hmm, I am 32 and have donated 6 times per year for the past 8 years. I don’t know my ferritin, but today there was a new placard at the hospital stating they test it, and you just have to call about 3 days after donating.

john p lushefski says January 8, 2019

Update: my ferritin is 31.

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