Pernicious Anaemia Society
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Active B12 tests


I cannot find which tests to have and where to order them from - to check active B12.

I supplement and inject 'sometimes' (cyno and B complex) - cannot do IM myself and so have to rely on when I can get someone (friend / family) to do it for me - but consequently my 'serum' b12 is always high.

I have had odd blood tests for a while - high RBC,, high Haemaglobin and haematocrit. One test was within the normal ranges and I think that this was when I was having regular injections - but then the RBC width was large.

Does any if this make sense to anyone.

Thank you.

4 Replies

Do you have the results and ranges for the tests you are referring to.

I wouldn't bother with either active or serum B12 if you are injecting - both will be distorted by the injections.

what are your symptoms and how do they change in relation to the timing of injections?

do you have any other conditions - eg hypothyroidism?

Do you know what is going on with your folate and iron levels?


Hi - thanks for your response.

My iron hardly ever gets tested - but the last was 18umol/L (range 10-30)

My Folate was 15.6ug/L (range 3-20)

Note these have been consistently high over the last year and a half - except for the one test when I was regularly injecting.

These are the last tests I had:

5.55 10*12/L (range 3.8-5)

Haemoglobin 163 g/L (range 115-145)

Haematocrit 0.49 L/L (range 0.36-0.46)

When the above 3 were just within normal (March last year) then my RBC cell width was too large: 16.3% (range <14.5) and my serum iron was 19.7. I think I was taking iron - as my serum iron had been a bit low before.

It was when I was injecting - I had just started steroid treatment for the PMR and was also doing Aqua physio so probably breathing better and getting more oxygen too.

I am hypothyroid (Hashimotos). Have Psoriasis and currently on steroid treatment for Polymyalgia Rhuematica (PMR) - also autoimmune.

At the moment I havnt had an injection for a month and feeling very dizzy, light headed and have air hunger (feel like I can't get my breath)

I'm generally low on Vit D and usually supplement.



I think you really need to talk to your GP or a haemo - there are a number of things that can cause high RDW and very few of them are related to B12 or folate and your iron is looking quite good.

It may be that you need injections a lot more frequently than monthly.

Injections don't have to be done IM - they can also be done sub-cutaneously if that is easier.


Thank you. Am seeing a Haemo - they are monitoring.


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