B12 Deficiency Symptoms - is this possible with 'normal' levels?

Posted , 4 users are following.

Hi guys, I'm just curious - is it possible to still have a B12 deficiency/many of the symptoms that go along with this, but still have what is considered a normal Active B12 level?

I had a whole raft of blood tests done for B12 deficiency and an autoimmune disorder but all came back as normal. Many were near the lower end but still, fairly normal. I'm seeing a private GP, as my own one has been nearly useless and he is adamant that my symptoms show the above and is keen to treat with B12 injections, folate and vit D despite the results being relatively normal.

Is this possible?

1 like, 2 replies


2 Replies

  • Posted

    Sorry I cannot answer this -I am the opposite have high B12 levels in blood but have a B12 deficiency due to surgery many years ago. It may depend on what your other symptoms are that may suggest your private GP is looking at a B12 deficiency. You could try an injection and folate to see if they stop your symptoms. 
    Report Reply
  • Posted

    Do you know what the level of active B12 was?

    The limits for active B12 are about 1/5 of the levels of serum B12 as it just measures B12 that is bound to the protein that allows it to pass from blood to cells - which tends to be about 1/5 of the total B12 in your blood. 25 is about the bottom of the range for active B12 

    You could always ask for an MMA test. Methylmalonic acid is a chemical used up in one of the cellular reactions mediated by B12. If there's not enough B12 in the cell then MMA levels will rise. If they're not high then it means your cellular levels of B12 are OK. High levels of plasma MMA (>0.75umol/L0 almost invariably indicate cobamalin deficiency

    The uMMA test measures the amount of MMA in the urine or blood.  Elevated levels of MMA indicate B12 deficiency.  MMA is 40 times more concentrated in the urine than the blood, and the urinary MMA  (uMMA) is the preferred test over the serum MMA.

    The new BCSH guidelines say: “Plasma tHcy and/or plasma MMA, depending on availability, may be considered as supplementary tests to determine biochemical cobamalin deficiency in the presence of clinical suspicion of deficiency but an indeterminate serum cobamalin level”.


    I am not a medically trained person but I've had Pernicious Anaemia (a form of B12 deficiency) for more than 46 years.

    I wish you well.

    Report Reply

Join this discussion or start a new one?

New Discussion Reply

Report as inappropriate

Thanks for your help!

We want the forums to be a useful resource for our users but it is important to remember that the forums are not moderated or reviewed by doctors and so you should not rely on opinions or advice given by other users in respect of any healthcare matters. Always speak to your doctor before acting and in cases of emergency seek appropriate medical assistance immediately. Use of the forums is subject to our Terms of Use and Privacy Policy and steps will be taken to remove posts identified as being in breach of those terms.