Pernicious Anaemia Society
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Trial B12 injections

Hi, I was wondering if anyone could offer advice if they have any experience of being given B12 injections even though their blood test results are normal? My wife has been quite unwell since January and her symptoms match PA as well as her having a family history of PA.

She has had many other tests and is waiting on many more but the Doctors are a bit perplexed. We're feeling it might be that she needs B12 injections. How have people gone about getting these if their blood test for B12 is normal? Many thanks for any advice offered.

6 Replies

What was the result? If under 200 BCSH suggest treating. It would be advisable to ask for methylmalonic acid test. Also a holo transcobalamin test can be ordered via StThomas' hospital in London.

BMJ article suggests treatment even if results don't all add up but better to get the tests first if possible.


First question is what was normal - the serum B12 test is known to be an inaccurate indicator of B12 deficiency which is one reason why the recommendation in the UK is to treat on basis of symptoms - the other is the risk of permanent neurological damage if the deficiency is left untreated.

significant numbers of people show strong clinical signs but test results are in normal range - anything under 450 and MMA and homocysteine are good follow up tests to confirm - they are waste products that build up if the body doesn't have enough B12. 450 means quite a substantial area of the normal range is actually a grey range.

This is the reference to the NICE guidelines on interpreting serum B12 results

Unfortunately it isn't as clear as it cold be as the focus is on anaemia which is a bit unfortunate but you could try combining that with the summary advice from BCSH which can be found here

to argue for a trail.

Other things to consider in supporting case would include any family histories of B12 deficiency as it can frequently run in families (eg if caused by B12 or abnormalities in the ileum).

You should also consider the possibility of drug interactions - eg omeprazole used to treat acid reflux, gabapentin used to treat spasms etc - that can actually inhibit absorption of B12.

I presume you have had folate levels tested - these do need to be good as body needs B9 to absorb B12 and the two are used together for a number of the key processes that go wrong.

You may also find the advice on this site useful


I persuaded my GP to let me have a trial injection (one only) and as a result I felt great for a couple of weeks. The GP then said as it was only for two weeks, the effect must have been placebo, and flatly refused to let me have any more.

I now have an appointment to see a haematologist in June, 13 months after this all started last year.


Hi Sam,

Good luck with helping your wife. It's great that you are supportive.

The above website was set up by a uk sufferer. She has advice for people who need to write to their GPs if their treatment is not satisfactory.

Has your wife had IF (Intrinsic Factor) tests? They can come back negative but it is possible to have PA with negative IF tests. The BSCH guidelines refer to this as Anti-intrinsic factor antibody negative PA.

Another useful document may be the UK NEQAS B12 Alert. This makes it clear that severe neuro damage can occur with normal serum B12 levels.

The PAS (Pernicious Anaemia Society) website has some useful documents that you could pass on to the GP. It also has a section aimed at medics. There is a symptoms list that I plan to give to my GP in yet another attempt to get a diagnosis. For some of the documents you need to be a member to get access.


Hi Sam, yes, I receive monthly B12 shots although I had 'normal' B12 blood tests (384). I had to compile a dossier for my doctor, giving my argument as to why I felt I should receive treatment and I backed this up with all the papers I could find to support the various parts of my argument.

I suggest you establish three things 1) that the results are not normal. In my case I was under 400, and the standard treatment cut-off in Japan, for example, is 500. You can also cite various B12 experts and what they feel is a healthy cut-off point and how far this is from NHS levels. 2) Why your wife needs them. You would need to show some pressing reason, like neurological damage, or some other condition that might indicate serious damage could be done. Her family history could be used here also. 3) That if your wife is on medication, or is about to be put on medication, that B12 will be safer and much cheaper. It is not toxic and it is not possible to overdose on it. If it will be done instead of medication then this is easier to fight for, particularly if the medication is dangerous or creates health problems of its own.

Feel free to ask me anything about how I won my doc over, but I warn you now, it's not easy and it was not without an (ongoing!) fight.


P.S. I should just add that I would not commence any treatment without first getting Homocysteine & MMA tested - you may well need these later and they will give you useful information and help you to be taken more seriously. I got treatment without these and not a day goes by where I don't regret my decision!


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