Active B12 test

Hi everyone

I have a strong family history of PA and what I suspect are symptoms but as my results are low but in range the doctors have refused to treat me. I have supplemented with B12 sublingually for the last 9 months but I am still symptomatic.

I am considering paying for the active B12 test privately but wanted to know if it's worth me doing as I have been supplementing? Will the results be skewed because of this, making them worthless?

Many thanks in advance for any advice anyone can give.

10 Replies

  • There are some sources that say that the active test will be influenced if one is supplementing with B12, and other say it won't be.

    However, I would recommend that, instead of the ActiveB12 test you get tested for MMA (methylmalonic acid) and possibly total homocysteine. Both these tests will give a darn good idea as to whether or not the B12 in your system is doing its job. High levels of either are a fairly good indication that whatever B12 you have isn't working as well as it should.

    The MMA test is easier and, probably, cheaper than the HomoCys (where the test must be run within 2 hours of the sample being taken).

    It would also be a good idea to get tested for anti-Intrinsic Factor antibodies. A positive result is a very good indicator of PA. A negative result isn't (about 50% of people with ther antibodies test negative).

  • Thank you that's really helpful. I had never heard of these tests so will look into them. I would like to think that my GP or Endo could ask for them on the NHS but I would imagine that it's more likely that I will need to pay for them.

    Thanks again.

  • The MMA test should be available on the NHS.

  • I will be requesting this at my next appointment then! Thank you.

  • I have read different views on this.

    I feel I wasted a lot of money on private blood tests after I had been taking B12 supplements and suspect the B12 had affected the results.

    I also wonder if they should have been fasting tests and I had eaten breakfast.

  • That's what I was worried about - especially as I am supplementing with a high dose.

    That link was really helpful thank you. I don't know much about the different types of testing so need to educate myself. That way I might have some hope of getting some help from the 'experts'!

    Thanks again.

  • I once found advice on the website of a manufacturer of Active B12 tests that the levels of Active B12 were likely to be high if taking B12 and advising that taking B12 should be stopped for a period before taking Active B12 test.

  • This link may be useful

  • Thanks again :-)

  • I'm going to be interested in my results for ActiveB12. I would guess that a low active B12 could be caused by two things - low B12 or low TC2 (the protein that binds to B12 to form holotranscobalamin).

    I have a mutation on the TCN2 gene that hinders the production of TC2, so I'm wondering if that might mean low ActiveB12 despite sky-high levels of B12 in my blood.

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