Log in
Pernicious Anaemia Society
17,178 members11,886 posts

B12 Checking levels or Symptoms

For some time now am being treated with B12 injections for B12 deficit but not PA is there any specific test to see how things are going in respect to B12 and Folate and Ferritin in any type of test etc?Obviously i can't check B12 levels from blood test as it would be incorrect and i would imagine i would need to be careful that the GP doesn't look for an excuse to stop treatment too.

4 Replies

You are right to be cautious I suspect, although hopefully the GP will know the guideline that treatment should not be stopped because of high levels.

There are more accurate 'active' B12 tests which apparently can give an idea of how much B12 your body is actually able to get - compared to the level in the blood, but they don't seem to be readily available. I'm not sure they would tell you anything extra in any case, and under the guidelines at least would not lead to an increase in dosage (though some people do seem to need it more often)

If you are not being treated with folate, then a test for that may well be a good idea, as I've read that it can drop once B12 replacement starts. A check of Iron/Ferritin can't hurt either, although I'm not sure there is necessarily a clear reason to do so unless you are symptomatic?

How long have you been on the treatment? Are you finding that the symptoms are being kept at bay by the treatment?, or returning sooner than the next dose (I assume you're on 3 monthly injections?)

Others who have been on their treatment longer will hopefully be able to offer more advice (I'm only just starting on the loading dose).


1 like

active B12 unlikely to be useful if on maintenance doses

tests that could clarify/identify a functional B12 deficiency (raised levels in serum but not enough available to cells are MMA and homocysteine but these can be elevated for other reasons - including folate deficiency in the case of homocysteine.


Hi Gambit62

So you suggest also a MMA test with homocysteine with also folate ferritin and iron would be useful?

thank you for your support .


Hello GavinUK

thank you for the explaination which is interesting ,i am on B12 injections every 2 months and my symptoms return a just over a week before my injection is due .I will look into folate and iron and ferritin update blood test to check things out.

Good luck with your loading doses and if you do have symptoms like myself pins and needles at night in hands or migraine Aura ,do make sure your GP ,after your loading doses ,can get you B12 injections every 2 months ,if not every 3 months is the GP standard approach which i am sure your aware of.

Thanks for your helpful advice.


You may also like...