Pernicious Anaemia Society
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Iron deficiency anaemia and b12 deficiency

I have had a serious bout of iron deficiency anaemia when my haemoglobin count went down to 6 and I had to have 2 blood transfusions.

Before that I thought I might have B12 deficiency because of some symptoms which were probably anaemia, but also because of numbness and tingling in my feet. My GP said that my B12 level at 150 was within the normal range, which is what the lab which does their tests regards as within the normal range.

I was overtaken by the diagnosis of mycrocytic anaemia, which they were very clear meant that I did not have B12 deficiency. The doctor who diagnosed the anaemia said my B12 count was 299 at that point.

I am now taking ferrous sulphate and have stopped taking the PPI and anti inflammatories which I was taking.

My Hb count is now 14, but on my most recent blood test my B12 level is 115, which is still within the normal range according to the lab.

The numbness in my feet is getting worse, but my GPs say it could be a number of things.

What I don't know is whether I could have clear iron deficiency anaemia which somehow was masking B12 deficency, and how I persuade my GP that 115 is not a normal level.

7 Replies

I don't think there is any masking going on just woeful ignorance on the part of your GP - many people can be B12 deficient at levels well into the 'normal range' so it may be worth drawing your GPs attention to this alert from UKNEQAS - the organisation that monitors the quality of blood tests in the UK - which clearly states that you cannot rely upon just the figures in using the B12 serum test to diagnose a B12 deficieny

Macrocytosis is one of the classic symptoms of a B12 deficient. It is a form of anaemia where the body isn't actually creating red blood cells properly - so they are larger and rounder than they should be. This makes them less efficient at transporting oxygen around your body and may be the explanation of some B12 symptoms. The neuro symptoms you describe are probably the effect of B12 on your nervous system as B12 is used by a large number of systems in the body.


I had several blood tests while I was anaemic, at my GPs and in hospital when the blood cells were smaller than normal size. I also saw those tests which I was told and read meant microcytic anaemia which is likely to be caused by iron deficiency anaemia and unlikely to be caused by B12 deficiency as that would be macrocytic. I suppose I am trying to work out whether I could have gone from one to the other in a couple of months


thanks for clarifying - had misread as macrocytic anaemia.

Anaemia isn't always one of the first symptoms to appear - I had 40 years + of other symptoms before a B12 deficiency was finally diagnosed and I've never had any macrocytosis.

The most likely explanation is either that there is a general absorption problem that is affecting both B12 and iron ... or that there is actually more than one thing going on.


Thanks for that. I will have to see if I can persuade my GP of that. The hospital hasn't really identified the cause of my anaemia, but have suggested stopping the anti inflammatories I take for osteoarthritis as being the most likely thing to help, which hasn't exactly helped with my general well being


interesting - B12 deficiency can result in osteoarthritis ... though I suspect your GP would totally dismiss that as a possibility.


Yes I think it is possible for an iron deficiency - particularly one as serious as you had - can mask a B12 deficiency. Do you have normal ranges for that 115 level? Have you got a copy of it?


I think the bottom of the normal range according to the lab is 100. I have seen it and there is a very wide range. Everything I have read indicates 200ng/l is the lowest level below which it should be regarded as a deficiency, paricularly if there are other symptoms,which I have.


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