Can Losing Blood in Tests Cause Iron Deficiency?

For a person suffering from Anemia because of iron deficiency, my mom thinks the reason my numbers barely improved in 8 months on iron pills was that I kept repeatedly getting blood tests throughout that time. Checking my iron, thyroid, CBC, Vit D, you-name-it. Didn’t keep track of how many vials of blood was drawn during that time but it seemed like every month I went to get tested for something or other, sometimes multiple vials.

My question is, for us iron deficient people, do you think getting blood drawn on a regular basis is enough to halt our progress? I know the medical professionals always say it’s a negligible amount and it doesn’t matter. They say the same thing about our menstrual cycles too, but we can all attest that we feel worse at that time of the month! For a normal person it may not make a difference, but for someone who’s already low, it makes sense that it might be hindering us. I just wanted to hear your thoughts. Wondering if this could be part of the puzzle for why iron pills aren’t working.

Deficiency 4 Answers 2569 views 1

Answers ( 4 )


    I disagree. Our bodies regenerate blood. Now, if they were doing it every day then I could say that could be a possibility.


      It does regenerate, however, every time we’re losing blood, we’re also losing iron. That’s why donating blood can trigger or worsen anaemia (it did for me). I guess every little drop of blood is very precious to us, iron deficient people!


        It takes 3 or 4 weeks to regenerate that blood also so if you’re giving full vials.
        every couple of weeks, it does affect it.


    I tend to agree with this. My husband has hemochromatosis which is too much iron in the blood and he goes for regular phlebotomies to get his numbers down. They usually take 500mls, sometimes 1 litre. But I’m not sure how much would actually be taken in those small vials. Interesting concept though.


      10-15cc max is less than a period for labs.


        So if you have 2 tubes of blood removed that 10-15ml of blood, that’s approx 3-5 days of iron: now In a well woman that shouldn’t be a problem but in an ill patient taking blood away is an issue. For you, it is probably not contributing Over months but highly appropriate as a huge factor in the patient needing regular tests.


          Thank you, Roger, great information! So you don’t think monthly bloodwork would cause a person’s Ferritin to only move from 18 to 24 in 8 months?


    There may be absorption issues. My hematologist-Oncologist said always take it with Vit C (or any food/drink high in ascorbic acid) because iron can’t be broken down and absorbed without being in an acidic environment. Also take iron at least 2 hours away from dairy/calcium, which inhibits absorption as well. Taking iron with caffeine from any tannins (coffee, tea…) can lessen efficacy, so you need to make sure you’re taking it with the right food/drink at the right time to make a difference.

    Not so much fun really. Your stomach has to have the right environment to make the iron available in your body, so you can take iron regularly and not see the benefits if, for example, you take it with a breakfast of yoghurt and coffee. This also means that acid-reducers, like Prilosec or Zantac, can make it hard to have enough acidity to absorb iron easily. Vit C helps with this.


    In general if iron pills “aren’t working” it’s because of you
    1) aren’t absorbing them
    2) are absorbing them but are losing too much blood somewhere
    3) have some genetic component messing with iron regulation.

    That’s what I’d be thinking off the bat. The thing with blood loss is it can be hard to really know EXACTLY how much we’re losing even doing our best to keep track. I also would like to know what that official “tipping point” is for when the blood loss is officially outpacing the amount of iron we can absorb from pills (even under ideal circumstances).

    As for those blood draws, it’s hard for me to believe those tubes hold as little blood as they insist because it just looks like so much more!!!

    Best answer

      I know! Would an MTHFR mutation inhibit iron regulation? The thing that annoys me is that I have been totally fine up until having babies. I’m like if it’s a genetic mutation causing it, why did it only show up postpartum?
      And I have no gut issues to my knowledge, and periods seem totally normal. Confusing. It seems like I just lost A LOT of iron during pregnancy/birth, but entirely clueless why my body doesn’t seem to want to replace it

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