what to do about macrocytosis?

Finally got repeat results back that confirmed my B12 levels are good (700-ish) and iron is pretty good. D3 is low but that's being worked on. Still have macrocytosis, high MCH and MCV, low red blood cell count, low white cell count. I think I understand that this means the count on the red cells is low, and the cells are extra large, and there's more iron per cell than "should" be?

Is there anything needing to be done (or that can be done) about the macrocytosis? Seems like it would be a risk for heart problems? Don't know.


8 Replies

  • Just wondered if your folate has been checked recently. Both folate deficiency and B12 deficiency can lead to macrocytosis.



  • Great question! My folate levels are always great. (?)

  • Hi Ashweb,

    Do you get paper copies of all your blood tests? I do after finding out that what I was told was "normal" sometimes wasn't when I got a copy of the results. I also find it useful to track changes in my blood results over a year or more.

  • yes, I do. Folate was 10.7. B12 was in the 1900s, which is why I had it repeated b/c I had taken a sublingual tab that morning, and the second result was 700-ish, which is right where I usually am when I'm doing a good job of supplementing.

  • That's a nice experiment on how effective sublingual B12 is at reaching the blood :)

  • The problem with macrocytosis is the deformation of the blood cell which means that the surface area per iron content is lower meaning that they aren't as efficient as they should be in absorbing and then releasing oxygen ... so your cells are a bit low on Oxygen - particularly if you combine that with the lower blood cell count.

    Your folate is sort of okay - certainly wouldn't describe it as great. Try to take a look at your diet and see if you can get any more into your diet as that tends to be the best source.

    Not sure how longyouhave been aware of the B12 problems and hence how long the anaemia proper has been going on. The macrocytosis is caused by the body not having enough B12 for all the cell reproduction that it needs to do so things start to go adrift and if it has been going on for a while then it is obviously going to take a while for things to correct themselves. The process also involves using folate so ideally you need to keep your folate levels high as well.

    One thing to watch out for - GP should be looking out for it - is that other vitamins and minerals don't become deficient - eg potassium.

    I'm really not an expert on bloods and I think you really need to work with your doctor as there is an awful lot than could potentially go awry and a lot of things to try and balance ... and there is always the possibility that B12 isn't the only thing that is going on.

  • This is GREAT info. Thank you! I can't get my GP even interested in the macrocytosis. My GPs have always been content once my serum B12 levels are better and they just say that high MCV and MCH just "come with the territory" of B12 deficiency. My low B12 (200) was discovered in 1995. Pernicious anemia Schilling test was negative.

    I've been taking shots monthly for years and since I know my habits are to be rather non-compliant, I've found that 5000 IU of methylcobalamin sublingually daily works better for me. I stay right around 600-700+

    I have a tendency toward iron anemia too. Seems that when I gave up wheat (I don't have celiac but I just feel better and IBS is not as bad if I avoid wheat), the iron absorption from my diet improved. My levels aren't stellar but they're like 36 hematocrit with a 50 serum level. (got down to 20 once with half-marathon training) I take multi-gen when I'm feeling deficient in iron.

    If I want to add a folate supplement, is the recommendation like 400 IU?

    I'll see if I can find a potassium score in my labs...


  • Glad to hear that cutting out the wheat helps - does sound like you general absorption problems so not surprising you have problems with B12.

    I supplement folic acid and actually use 3 times the dose you suggest. upper limits tend to vary from country to country - main reason for upper limit tends to be the risk that it will mask macrocytosis caused by a B12 deficiency so bit irrelevant.

    The best forms of folate come from food so take a look at your diet and see if you can up folate rich foods would be the first step. A methylated format might help more but it is something to approach with caution as some genetic variations that affect your ability to methylate vitamins (mainly B9 - folate - and B12) can lead to an adverse reaction to methylated forms of B9

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