Pernicious Anaemia Society
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Active B12 Test

Hi Everyone,

I was diagnosed with Pa 15 years ago and have had regular B12 injections at my surgery since then. To begin with it was every 3 months, then the symptoms got worse and my injections were changed to every 2 months and then last year the same thing happened and my doctor changed it to once every month. Since then my general health has been a lot better, not so tired and not picking up every minor illness going. However, all the old symptoms have come back in the past few weeks and I am off work again. Extreme tiredness, brain fog, dizziness, cant get up the stairs without sitting down for a rest. My doctor suggested having the Active B12 test done because he thinks it may be that my tissues are not taking up the B12 in the injections effectively. and asked me to get it done at the surgery today. So I turned up this morning but the surgery have said it can only be done privately. I have sourced a hospital near me that will do the test for a cost, with a referral from my doctor. So that's the good news.

My query is this..... I have read on this site somewhere in a post, that you need to stop your Vit B12 injections for a period of time, before having the test done as it can give misleading results if you don't..... is this correct please?

The lab manager from the hospital I have spoken to has said I do not need to stop having my injections before I have the test done.... hence my question...

If anyone can shed any light on this I would be very grateful..

Many thanks.

4 Replies

The NHS will do active b12 testing in some places -


Thank you very much!


There seem to be varying views on this - this lab advises not to take B12 for 24 hours before the test and to state in the form if supplementing within a month of the test:

Page 3


Thanks a lot!


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