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Pernicious Anaemia Society
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LOW mchc & mch with low b12?

I just received a copy of my blood test results and am hoping you all can help me understand. When I met with my gp last week he said I had b12 anemia and so started me on a 2500mcg Daily Dose. However, my results don't seem to match.

Mch 25 (27-34)

Mchc 30.3 (31-37)

B12 268 (232 - 1245)

Hemoglobin is in the normal-low range at 12 (12-16) and all other cbc counts are within normal limits, including mcv. It was my understanding that you need hemoglobin to be low in order to be anemic, and b12 causes high mch/mchc not low. If it matters, I do have quite low vitamin d at 15 (prescribed 50,000iu weekly) and high cholesterol at 167. I'm 31, female, workout and not overweight. Also should maybe note that my iron levels were not measured, and tsh is normal but "not ideal" at 3 (.45-4.5).

I originally went to my GP complaining of chest pains, arm numbness, extreme daily exhaustion, new anxiety, intolerance to loud and repetitive noises, dizziness, forgetfulness and breathlessness. I obviously don't want to go back and tell him he might be wrong, but I would really like to feel normal again asap.

Thank you all for any insight you might have!!

10 Replies

Hi Jbunn58 was your Folate tested?


It wasn't!


There are different types of anaemia - iron based anaemia results in smaller cells containing less haemoglobin - microcytic anaemia. B12 deficiency results in larger rounder red blood cells - result of something going wrong in the processes that control the production of new red blood cells in your bone marrow.

When you say your TSH was normal - are you being treated for a thyroid problem or not. Lot more on thyroid on TUK, but TSH is only one, rather indirect measure that can be useful in deciding where to look but doesn't tell the whole story.

Agree that your results suggest iron based anaemia rather than folate/B12 based anaemia.

Are you based in the UK - high dose oral isn't licensed as a treatment in the UK but is increasingly common in US, though there are some serious question marks over whether it really is an effective default treatment as it doesn't seem to work for everone with absorption problems.

It may be that your GP is acting on the basis of symptoms and a serum B12 that is low in range - 25% of people with B12 deficiency have serum levels that are inside the normal range. It may be that in talking about anaemia your GP is talking about 'pernicious anaemia' which is a bit of a misnomer as macrocytic anaemia is a symptom that isn't present in 25% of people first presenting.

However, I can only speculate about what was going on in your GPs mind and what is being said - you really need to have a conversation with them and/or ask for a second opinion if you think their diagnosis is wrong.


Thank you so much for this! I am in the US. I will certainly take this info into account when I follow up with my gp. Thanks again for the clarification!

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I wondered if the iron deficiency could be masking the effects of B12 deficiency on red blood cells.

Low iron can lead to microcytosis (small red blood cells). Low B12 (and low folate) can lead to macrocytosis (enlarged red blood cells).

Have you had a Full Blood Count (known as Complete Blood Count in USA) and a Blood Film?


patient.info/doctor/periphe... (UK info)

I am not medically trained.

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Thanks for this! I, too, am curious about iron deficiency. I am going to request the full panel from my gp because that does in fact make the most sense I think. Thank you!!


Hi there, i am in the US also.

If you have macro and micro sized red blood cells from having low b12 and low iron your mcv can present as normal. I would suggest looking at rdw on your cbc to see if you have both.

12 for hemoglobin is at the very bottom. Please ask your doctor for a complete iron panel.

If you have both iron and b12 deficiencies i suggest you get tested for h pylori. I was positive with only a b12 deficiency (level 169) and no stomach pain which is the most frequent symptom.

I could no longer workout (had stopped appox 18 months prior to getting b12 tested) and was barely getting thru my days at work.

Also... make sure you follow up with another b12 test in a month or 2 because the tablets i was told to take were not being absorbed due to h pylori and i just got worse and worse before going back to the doctor 16 months later.


Interesting!! My son was recently tested for h pylori, coincidentally. I will be following up soon and will definitely mention it. Thank you so much for your input and I'mglad you're feeling better!



Iron studies (some info may be UK specific)


Have you had tests for ferritin and folate recently?

Folate Deficiency (some info may be UK specific)


"chest pains, arm numbness, extreme daily exhaustion, new anxiety, intolerance to loud and repetitive noises, dizziness, forgetfulness and breathlessness"

Symptoms of B12 deficiency



Risk factors for B12 deficiency and PA (Pernicious Anaemia)




B12 books I found useful

"What You Need to Know About Pernicious Anaemia and B12 Deficiency" by Martyn Hooper

Martyn Hooper is the chair of PAS (Pernicious Anaemia Society). Book is up to date with UK b12 guidelines.

"Living with Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper

Has several case studies.

"Could it Be B12?: An Epidemic of Misdiagnoses" by Sally Pacholok and JJ. Stuart (USA authors)

Very comprehensive with lots of case studies.

PAS (Pernicious Anaemia Society)

Based in Wales, UK but has members from around the world.

PAS offers support and info about PA.


PAS tel no +44 (0)1656 769717 answerphone

B12 Awareness (USA website)


Lots more B12 info in pinned posts on this forum.

Coeliac Disease (Celiac in USA)

Have you ever been tested for Coeliac disease?

In UK, medical guidelines suggest anyone with unexplained B12, iron or folate deficiency should be tested for Coeliac disease. Two first line tests are recommended in UK.

1) tTG IgA

2) Total IgA

In UK, my experience has been that Total IgA test is not always done but it's very important as people with IgA deficiency need to have different tests for Coeliac disease.

Coeliac blood tests (some info may be UK specific)


Auto-immune conditions

If there are auto-immune conditions in the family, have these been excluded as possible diagnoses?

Good luck with getting answers. I think so many of us end up having to be medical detectives to find out what is wrong with us.

I am not medically trained.


Thank you SO MUCH for this information!! Wow I'm blown away by this and all the resources you've shared. I so appreciate it!!!


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