Pernicious Anaemia Society
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Testing for Homocysteine & MMA

After battles with my GP re B12 and my most recent blood test (700) I was told I did not need any further injections. I had been requesting them more frequently because of tingling fingers and toes, brain fog, tinnitus, blurry eyes, etc! I argued that I would accept her ruling if I had a definite diagnosis and suggested that blood tests for homocysteine and MMA, I had read, were the way to go. To my surprise I have just received a letter asking me to present myself for a fasting blood test before my next injection due date but that I must be prepared to 'rush' it to the local hospital as it had to be tested within 30 minutes of extraction. I take oral supplements and sublingual spray and would bea most grateful for any advice or comment.

6 Replies

As you've already been receiving injections, your homocysteine should have normalised within the first week (see *below) but the fact that you're still having neurological symptoms means that you need more frequent injections 'until no further improvement'*

Page 4 under Parenteral treatment *.

" Standard initial treatment for patients without neurological involvement is 1000 μg intramuscularly three times a week for two weeks. * If there are neurological symptoms then 1000 μg intramuscularly on alternate days should be continued for up to three weeks or until there is no further improvement.4 25 In irreversible cases, for example, pernicious anaemia, the treatment should be continued for life."

This treatment for neurological symptoms is also confirmed 'until no further improvement in the BNF/BCSH guidelines.

Re. test for homocysteine - bottom of page 3:

"Total homocysteine

"Plasma total homocysteine can increase early in the course of deficiency. It is a sensitive but non-specific marker and it is also high in folate deficiency, B6 deficiency, renal failure, and hypothyroidism. Most laboratories regard levels >15 μmol/L as high, although the reference range depends on the individual technique. The sample must be processed within two hours, which may inhibit the usefulness of the test."

Response to Treatment :

"*Homocysteine or methylmalonic acid should normalise during the first week of treatment. Failure to do so suggests an incorrect diagnosis, unless renal failure or other causes of increases in the metabolites coexist. Cobalamin and holotranscobalamin levels are not helpful because they increase with vitamin B12 influx regardless of the effectiveness of treatment,24 and retesting is not usually required."

I hope the above helps clarify.


Hi Beattie-75. I agree with Polaris on both counts: your homocysteine levels will have reduced (likewise the MMA) due to the B12 injections you've been having and the result will therefore most likely be normal.

And as you still have neurological symptoms, you need more B12 (so you're right about that)!

Your GP is wrong to stop your injections! Your serum B12 level is not too high - I have injections and my level is always over 2000! To put this in context, In her book 'Coild it B B12....' Sally Pacholok states that B12 levels should be over 1000 (some say over 1500) to effect neurological repair.

In addition, your GP should be treating your symptoms, not your blood levels! All the guidelines state this (see NEQAS alert in the pinned posts).

Also - the thirty minute time limit is absolute! By the time you've driven there, parked, walked to the hospital, taken the bloods to the lab....

Unless you live next to the hospital it will be extremely difficult to meet the time limit. I had to go to the hospital to have my blood taken and even then it was a rush for them to get it down to the lab, booked in, and tested in time!

I think that the best course of action is for you to focus on the fact that you have neurological symptoms and aim to persuade your GP that you need more B12 because of this. If you read through the PAS pinned posts on the home page of this forum, you will find lots of information about B12 deficiency / PA and diagnostic and treatment guidelines your GP should follow. It might be a good idea to print the relevant ones, highlight the crucial facts and take them in for your doctor to read.

Also, the British National Formulary (BNF) gives detail of the treatment for B12 deficiency with neurological symptoms. Your doctor will have a copy on his / her desk, but will probably have to read further than usual to find it: it's the second item down!

Also - have you been referred to a neurologist? As your still have neurological symptoms it would be useful to check that these are not due to other causes.

I'm really sorry that you're in this situation. It's so commen here that some days I want to scream - but that's no good to you 😄.

Getting a definite diagnosis is very difficult and many of never do. It's much more important to get the B12 - injections, not sublinguals!

Please do not accept your your doctor's ruling - it's wrong!

Please keep fighting to get the correct treatment for B12 with neurological symptoms and post again if you need more help.

Good luck x


Thank you so much Foggyme and Polaris, so much to take in. As the GP is so sceptical about my diagnosis in Spain I have always been fighting a losing battle and just suggested the Homocysteine and MMA tests to try and confirm. She apparently contacted the Haemotologist at the local hospital who agreed with me! However as mentioned I am very unsure of the efficiency of getting the bloods into the hospital AND booked in, in time! Where do I go from here - more arguments?

1 like

Hi Beattie-75. Hmmm...I'm just wondering if your GP actually told the haematologist that you had already had B12 injections?

When I saw a neurologist recently he tested MMA and homocysteine but said that he expected them to be within the reference range (normal) as I was already being treated with B12 injections. And he was right. The results were normal (even though I was clearly not!).

So irrespective of the 30 minute rule and whether you get the sample to the hospital in time, I think you'll still have a battle to get B12 injections as, sorry to say, the results will probably not give you the answer you would like.

It's really bad that your GP has decided to stop your B12 injections. In view of your ongoing neurological symptoms and her refusal to treat those symptoms, she is being negligent!

So yes, I fear that more arguments are in store! Please post again if you need further advice or support.

Good luck and let us know how you get on X


Hi, I think it is good that she finally listened to you and went for the tests - a lot of doctors wouldn't. My haematologist recommended to my practice that I have these tests to monitor my levels - needless to say they haven't listened, just stopped my 8 weekly injections.

If it is possible to do so, I would have them done. What about freezing the blood prior to taking it over? Would that affect it?

Afterwards, the long and short of it all is - if it helps you - take more. :)


"received a letter asking me to present myself for a fasting blood test before my next injection due date but that I must be prepared to 'rush' it "

Just wondered if this blood test you mention is for Active B12 as I think the sample has to be tested soon after collection.

My understanding is that Active B12 test results are likely to be affected if you have recently had b12 treatment. See 4th question in link.

"After battles with my GP re B12 and my most recent blood test (700) I was told I did not need any further injections."

Google the "BCSH Cobalamin and Folate guidelines".

Have a look at page 29, a diagnosis flowchart and page 8 details of Uk B12 treatment. There is a link to this document in second pinned post on forum but page numbers are different due to its condensed format. I gave a copy of whole document to GPs.

The BCSH Cobalamin guidelines and a recent BMJ article on b12 makes it clear that people who are symptomatic for B12 deficiency should be treated even if b12 levels are "normal range". See 5th point.

Have you thought about joining the PAS? They can sometimes intervene by writing letters on members' behalf.


PAS tel no 01656 769 717

Link about writing to GPs

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


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