Pernicious Anaemia Society
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Question about anemia

Hey guys I'm sorry if my questions are silly but I don't know much about anemia outside of pregnancy 😊 basically been having some issues with thyroid and anxiety, my thyroid is now normal. my b12 was tested last month and I was told it was normal but I found out today it is 211 and anything less than 200 is not normal but I have read it needs to be above 500 so is this true? my doctor also ran a full blood count to check my iron levels as I've had a massive increase in migraine intensity and frequency (suffered with these from I was a child) and the blood had to be repeated in 4 weeks, not sure of the levels sorry. but my second question is could my b12 and iron levels both be low at the same time? are they related or treated as separate results? I know they're both to do with iron levels but really not sure of the difference in them 😁 all help and advice welcome thank you

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Hi leannemcc19

Yes you can have both anaemia due to an Iron deficiency AND have Pernicious anaemia / B12 deficiency - they are different things but both can affect the size of your red blood cells.

Iron deficiency anaemia is as it sounds an anaemia caused by a lack of iron. This can be because of various things including heavy periods, a diet with too little iron in it or being unable to absorb iron properly. Iron deficiency anaemia causes microcytosis (small red blood cells) and a lowering of things like your Haemoglobin (Hb) levels as iron is part of this. You can also have iron deficiency but not yet be anaemic. (It is the precursor of anaemia.) Doctors usually look at your Haemoglobin, MCV and ferritin levels (there are other iron blood tests too) to work out whether you have anaemia caused by this.

Pernicious anaemia (PA) is an autoimmune disease where the body produces antibodies against part of the body involved in B12 absorption (intrinsic factor) and the cells which produce this factor. It means that people with pernicious anaemia cannot absorb ~99% of the B12 from food and eventually exhaust the body's stores and become deficient and unwell. One of Vitamin B12's roles is in red blood cell (RBC) production. If the body doesn't have enough B12 the RBCs can be larger than normal (macrocytic) and an abnormal shape. B12 deficiency can also cause many other symptoms too.


It is very possible to have both types of anaemia at the same time. Having both smaller than normal and larger than normal red blood cells can mean your MCV is in the normal range as this is a measure of the average RBC size. You can also have PA and NOT have signs of anaemia, instead showing neurological symptoms! I wasn't anaemic according to my FBC results when I was diagnosed with PA but it looks like I was on the cusp of iron deficiency and a few months later became iron deficient too.

Your levels of B12 are quite low. I'd look the PAS website (see above) and see if you have some of the symptoms and discuss testing for anti intrinsic factor antibodies and starting B12 injections with your GP. Have a look at the PAS website or at the links here (on RHS if on a computer or at the bottom if on a phone) for more info and guidelines on how a B12 deficiency should be treated.


Thank you for the information, I feel my b12 is too low as well but the doctor said it was normal and now my hemoglobin is the low end of normal too so I'm trying make sense of it all. I will read it all properly when I am able to as at the minute I can't see straight and focusing on the writing and trying to take it all in is making me feel nauseous (I feel like crap today if you hadn't guessed lol) I am tempted to order some blood tests myself and see if I can get to the bottom of it, I have felt like crap for so long I am beginning to lose patience. sorry for the rant lol and again thank you so much 😊


The frequency and severity of my migraines increased when my B12 levels became very low just before diagnosis.

Are you supplementing folic acid at all?

The combination of high folic acid and an iron deficiency will act against any tendency to macrocytosis. Many GPs mistakenly think that if macrocytosis isn't present then it can't be B12 but, leaving aside the possible interplay of B12 deficiency and high folate/iron deficiency, 30% of patients will present with neurological symptoms before they present with macrocytosis. Diagnosis of a B12 problem has to involve looking at the clinical symptoms so put together a list of those. There may be some problems interpreting because of the overlap with thyroid conditions but if your thyroid is under control then it would seem unreasonable to be using that as an explanation for the symptoms.


on the other hand it is true that levels can appear low during pregnancy because so much of your B12 will be going to your baby so the low levels could be a result of the pregnancy rather than an absorption problem ... and that could make getting a diagnosis difficult as well - however, it's symptoms that really count.

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Thank you for the information. I don't supplement at all with anything, my hemoglobin is 121 and the range is 115-165 so it seems my b12 and hemoglobin are both the low end of normal, I have anxiety, tiredness, foggy, loss of concentration and memory, tremor in my hand and I read something about taking big gulps of air and I do have days where I do that, himself always thinks there's something wrong. my thyroid has been well maintained for years but recently my body attacked it and it went over active (it was under for 13 or so years and maintained with meds) and now it's normal but a lot of my symptoms have remained and I only mentioned the migraines as they have become so severe I'm unable to look after my children for days and I actually expected my blood count to be normal. it's so frustrating that everything is borderline and so unclear that's why I thought to check if the two levels were related but the information is all new to me so I don't know what to make of it but the b12 level concerns me as I don't want any lasting damage and the doctor won't test it again as it has essentially been ruled out as a cause of my problems as far as they are concerned. I will read all of the information you both have given me and hopefully can get my doctor to at least retest it in a few months or so and see if it's changed?


ask for your ferritin levels to be checked you can have normal haemoglobin and low ferritin my levels were 112 range 115-150 so not lots under my ferritin which is your bodies iron stores was 6 which is very low, worth checking


So is that how well your body uses the iron it gets?? is that the same as foliate or is that something different? I'll be honest I find it all really confusing. can you take b12 at home or does it have to be the injections?


I'm not an expert its been explained its how much stored iron you have it seems to run along with b12 deficiency a lot of people have both, its got nothing to do with folate though, my results for b12 were 140pmol l was offered no treatment at the docs so had to self treat, l couldn't self inject so take lozenges you probably wont get treatment at 200 most don't because of the lack of knowledge of our gps, most people are vitamin d deficient its worth asking to have that checked, l take iron b12 and vitd and its made a difference, the iron and vit d were fairly fast acting the b12 longer to take effect but do make a difference,


I've been told to check my vitamin d levels in relation to my hashimotos thyroiditis, it's so frustrating that the doctor says no the number on the screen is normal so you're normal and the reason I checked these levels is now irrelevant, you and your symptoms can go away lol seems like I need an awful lot extra tested and I know my doctors won't do it so I am considering paying to have them done privately and then supplementing. I am having a foggy brain day today so I need to wait until I've a clear head and read all about it and decide then but boy do I miss feeling normal! lol


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