Pernicious Anaemia Society
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Functional B12 Deficiency & MMA/Homocysteine Tests

I have un- (or badly) recognised B12 issues. Only this evening while trying to find some help on why I could still have problems even although I get 4-weekly injections, I discovered Functional B12 Deficiency. I don't know if I've somehow missed this (God knows how!) or it hadn't been given a name when I first did my research, but I suspect this could be my problem as it seems to fit to a T.

I have trigeminal neuralgia and have been in remission for over a year. However recently it's started to come back. I have also developed a numb leg problem and have various other odd little neurological tweaks that indicate all might not be well with me neurologically.

I had tremendous difficulty getting my doc to treat me for B12 (for the TN) but when I was finally treated with loading doses it worked really quickly. He, however, still does not believe it was relevant (he thinks it's a placebo effect).

I've discovered that if I have functional deficiency, MMA & homocysteine tests may actually be useful, despite my B12 treatment, as in they should show as elevated if I have the condition. Is this correct? Also, can my GP have these tests run or would I have to be sent to a hospital/consultant? If so, what do I ask for by way of a dept? Is it haematology who would do this, or neurology? Believe it or not, when I was first seeking treatment I asked my doc for these tests and he'd never heard of them and told me he couldn't get them for me. I have a horrible feeling if I'd had them done then all might have been revealed - although whether they'd have been acted on is still very open to debate!

I am seeing my doc (a different one!) in a couple of days to ask if I can go back to alternate day injections for a month as a preferable treatment to try before going back on Carbamazepine, so if anyone can give me any tips for what to ask for re MMA testing, I'd be grateful. I'd also appreciate any links for further reading on functional B12 deficiency if anyone has experience of this. Thanks!

P.S. I should just mention that I told the last neurologist I saw that B12 had helped me and he was beyond disinterested, so if it's a neurologist who does this testing I'm more than a little anxious about how to convince them I need this done!

6 Replies

Your Doc should be able to do the Testing for you. In the Related Posts to the right of yours above - there are 10 more posts on the topic of MMA and Homocysteine testing - maybe some useful tips there for more understanding. If you are on a phone then scroll down and down until you see the same heading .... MMA is usually a urine test. Homocysteine is not routinely checked in the UK so be prepared for a fight. Here in Crete - no problem - and mine was raised for sometime from 2004 - but lowered into an acceptable place after treating the thyroid and optomising vitamins and minerals.

Gambit62 talks about Functional B12 Deficiency - so maybe check her posts/replies.

Be well :-) - hope all goes well with the testing.


I swear Marz that it sounds like Crete should be a regular weekend break for thyroid and B12 people to nip across, top up their vitamin D (depending on time of year and serum status), purchase some affordable lab work, eat (in some, no doubt, delectable local places) and sleep. :)

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Not the best place for Thyroid if it is T3 you want - currently being restricted with prescription only. First time ever .... Everything else can be organised - even the accommodation - my studio :-)


Thanks for the link, Marz; I've been chasing that one already. That appears to be the only article on the internet on functional B12, despite it being, obviously, not very well-known. I've been trying to access it for the last couple of days but it's well locked down I even joined the BMJ to buy the damn thing and found it was £27 - too rich for my tastes. Very frustrating.

I've read most of the MMA posts but I'm going to scour again in case I've missed any!


If you go to PubMed and type Functional B12 deficiency, you get five pages of results. Many of these will be irrelevant, but there seem to be a few that might be of interest.

You can use the options at the left to filer so you only get those with abstracts, or free full text, etc.

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Thanks, Helvella. Believe it or not it wasn't till I was in the shower this morning I suddenly thought "What a numpty - you forgot to check PubMed". Talk about missing the bleeding obvious. So thanks for the reminder - I'm obviously not bright enough to get there on my own!

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