Pernicious Anaemia Society
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What should I ask my doctor to test for if I suspect I have B12 deficiency/Pernicious Anaemia

Hi everyone,

This is my first post and I would really appreciate your advice.

I'm seeing my doctor on Tuesday and was wondering how best to approach discussing B12 deficiency/Pernicious Anaemia, eg should I be asking for particular tests?

I've been suffering with really bad fatigue for the past two years now, to the point that i've had to give up work and have a non-existent social life. I've had various tests done but the doctor hasn't been able to pinpoint a cause. I've also found that my concentration and memory are very poor, I often feel very weak or faint and my muscles feel weak too. I had my B12 levels measured 6 months ago and they were 207pg/ml (197-771). As it was in the normal reference range I left it at that but more recently I've been experiencing other symptoms like heart palpitations, a rapid heart rate and a tingling/twitching feeling in my arms and hands and wondered whether this could be related?

Any help would be really appreciated.

Thank you :)

4 Replies

Hi jazzy89 Your six month ago B12 level was definitely "bumping along the bottom" of the range despite it being flagged "Normal" and your symptoms indicate that you may well be Vitamin B12 Deficient.

I'm not a medically trained person but I think you should list your symptoms present it to your doctor and ask him/her to re-test your B12, and B9 (Folate) levels. It would probably as well to have your iron and Vitamin D levels checked too as some of their deficiency symptoms are similar.

Anyone at any age, can become B12 deficient. However, certain people are at an elevated risk. They include the following:

Vegetarians, vegans and people eating macrobiotic diets.

People aged sixty and over

People who’ve undergone any gastric and/or intestinal surgery, including bariatric surgery for weight loss purposes (Gastric bypass).

People who regularly use proton-pump- inhibitors. H2 blockers, antacids, Metformin, and related diabetes drugs, or other medications that can interfere with B12 absorption.

People who undergo surgeries or dental procedures involving nitrous oxide, or who use the drug recreationally.

People with a history of eating disorders (anorexia or bulimia).

People with a history of alcoholism.

People with a family history of pernicious anaemia.

People diagnosed with anaemia (including iron deficiency anaemia, sickle cell anaemia and thalassaemia).

People with Crohn’s disease, irritable bowel syndrome, gluten enteropathy (celiac disease), or any other disease that cause malabsorption of nutrients.

People with autoimmune disorders (especially thyroid disorders such as Hashimoto’s thyroiditis and Grave’s disease) Type 1 diabetes, vitiligo, lupus, Addison’s disease, ulcerative colitis, infertility, acquired agammaglobulinemia, or a family history of these disorders.

Women with a history of infertility or multiple miscarriages.

Infants born to and/or breast fed by women who are symptomatic or are at risk for B12 deficiency."

Can you "see yourself" in any of the above people? Your title queries P.A. Do you have anyone in a direct bloodline with it?

Please come back if you have any more questions as there are others on here who will be bale to give you good advice.

I wish you well

1 like

make your GP aware that

a) the way the normal range is set and the variation in responses to B12 in the general population are such that the test is going to miss 25% of people who are deficient (and pick up 5-10% of people who aren't deficient) if the results are used on their own.

b) if they are looking for macrocytosis as a defining characteristic of B12 deficiency 30% of people present with neurological symptoms first, so also not a good way of ruling out B12 deficiency.

c) evaluation of symptoms is a key part to diagnosing B12 deficiency

d) other tests that can clarify B12 deficiency are MMA and homocysteine (which will be both be raised if there isn't enough B12 at the cell level - but they can also be raised by other things. Active B12 is another possibility but, as with serum B12, this focuses on levels in blood and doesn't give the full picture of what is happening at the cell level.

e) the test for PA is IFA but this is prone to giving false negatives about 50% of the time so a false negative is no proof that you don't have PA. GPCA is prone to both false negatives and false positives so even more problematic as a diagnositic tool.

f) other absorption problems that can lead to a B12 deficency include coeliacs and crohn's but if the cause is these then I would expect multiple deficiencies/low levels including iron and folate.

g) review any drugs you are taking to look for drugs that may be suppressing the absorption of B12 - such as metformin, PPIs, NSAIDs ... quite a long list infact. PPIs are a particularly problematic group as they can be used to treat low stomach acidity that has been mistaken for high stomach acidity and low stomach acidity is something that will also lead to problems absorbing minerals and vitamins.



Are you in UK? Some info below may not be relevant if you are elsewhere.

Causes of B12 deficiency

What to do next if B12 deficiency is a possibility?

BSH Cobalamin and Folate Guidelines

If you are in UK, I'd recommend reading the whole of "BSH Cobalamin and Folate guidelines". This is a UK b12 document that gives guidance to GPs about diagnosing and treating B12 deficiency and PA. Sadly some GPs are unaware of this document. click on box that says "Diagnosis of B12 and Folate Deficiency" should be on page 3 of listed guidelines

Link to flowchart in BSH Cobalamin guidelines.

Flowchart makes it clear that patients who are symptomatic for B12 deficiency should have an IFA (intrinsic Factor antibody) test and start initial B12 treatment. This applies to both those whose B12 is low and also to those whose B12 is within range. When your B12 was at 207pg/ml (197-771) 6 months ago were you given an IFA test?

The IFA test can help to diagnose PA (Pernicious Anaemia) but is not always reliable. It is possible to have Antibody Negative PA. this is mentioned on the flowchart above.

Have you looked at B12 deficiency lists? Do you have any of the symptoms?

pernicious-anaemia-society.... click on Symptoms checklist

B12 info

1) Pinned posts on this forum

2) PAS (Pernicious Anaemia society) website


PAS tel no +44 (0)1656 769 717

Might be worth contacting them before your appt. They can point you to useful info.

Martyn Hooper's blog

3) B12 Deficiency Info website

4) BMJ B12 article

5) Book "What You Need to Know About Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper.

Martyn is the chair of the PAS. Book is up to date with UK B12 guidelines. He has written other books about B12 Deficiency and PA.

6) Book "Could It Be B12" by Sally Pacholok and JJ. Stuart

Very comprehensive book about B12 deficiency.

7) BNF (British National Formulary) Chapter ( section 1.2)

8) When I first joined PAS forum, I spent time reading other threads.

Blood test Results

Do you get copies of all your blood test results?

I learnt to after being told everything was normal/okay then finding abnormal results on the copies. In relation to B12, I look at B12, folate , ferritin, full blood count (FBC). There can be useful clues on FBC that might indicate possibility of b12 deficiency, folate deficiency , iron deficiency.

Unhappy with treatment?

Link about writing to GP about b12 deficiency

Person who runs website can be contacted by e-mail.

HDA patient care trust

UK charity that offers free second opinions on medical diagnoses and treatment.

"wondering how best to approach discussing B12 deficiency/Pernicious Anaemia, eg should I be asking for particular tests? "

In past I have written letters to GP before an appt.

I gave my GPs a copy of PAS symptoms list with all my symptoms ticked and a copy of Martyn Hooper's book.

Perhaps GP would find flowchart from BSH guidelines helpful?

GP might consider ordering an Active b12 (holotranscobalamin) test. However if you are taking supplements that contain B12 the results of this test may be affected.

In the past, I would have taken someone with me who was supportive and knew about B12. I'd suggest reading up about B12 as much as you can before appt as sadly B12 deficiency is not always well understood by GPs.

I am not a medic just a person who has struggled to get a diagnosis.

B12 deficiency needs to be treated without delay. Untreated or inadequately treated B12 deficiency can lead to neurological damage. See link to BMJ article above.


Have you had your thyroid tested I have under active thyroid, some of your symptoms seem similar.


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