Advice on testing for B12


I'm in the process of getting my B12 tested privately, but would like some advice.

The Thyroid UK website recommends the active B12 test (holotranscobalamin), and also recommends using Nutristasis (now called Viapath?) for testing. I emailed them re tests, and am looking to get tested:

1) Active B12 at £18

2) MMA at £96

3) THCY at £40

Are these tests enough? Also, are the prices reasonable? Like most people, my budget is very limited but am willing to do this for my health!

They are also asking for a signed referral letter from the GP. Is this a simple process? My GP refused to refer me to the late Dr Skinner (thyroid specialist), and it was hell getting that sorted out.

Would appreciate any advice.

22 Replies

  • Hi BrecklandRanger,

    When my Daughter had active B12 tested (St Thomas' hosp London) she needed a request to have the test done by GP (He did do a letter as we said we'd pay, the results are sent to GP) and she initially only had the active B12 test done (£15,- plus VAT). As her result was in the grey area MMA was done. Her MMA was far to high resulting in B12 jabs for life. No need for homocysteine. So you could initially only have the active B12 test done and see what that results in before you pay for further tests you may not need. You can then decide on results if you want to have more tested.

    I hope this helps,

    Kind regards,


    Active B12 test at Viapath at St Thomas' Hospital , see:


  • Thank you for replying.

    I will point out to my GP that it's something I'm just looking into, and will save them money by paying myself. Hopefully they'll grant me permission.

    When your daughter's active B12 was borderline, did she have to return to St Thomas again? Or did she opt for it there and then?


  • My Daughter's active B12 was 28, because of that they tested (the same blood sample) her MMA. They dis not charge Us. My daughter was the first to have the test at St Thomas apparently, I expect they do normally charge, Marre.

  • I requested a letter from my GP and as I was prepared to pay it wasn't a problem.

    I don't think you need to ask for "permission" as there is no reason they can decline.

  • That's good. Just in case she does refuse me, I'll opt for the B12 tests that don't require a referral (although they're more pricey!).

  • There have been a number of reported cases of GPs refusing to give a referral for the Active B12 test. Seems ridiculous to me.

  • I hear you.

    I faced some resistance when I explored possible issues with my thyroid - testing and treatment, despite myself paying for it. Who would have thought that some Drs would deny us some autonomy when it comes to our health?

  • St Thomas will only see you if you're referred by the GP. If my GP won't refer me, am I able to get a referral via a private GP? (or anyone else?). Thanks.

  • HiBrecklandRanger ,

    You can get a referral from a private GP and or haematologist I expect, but it will cost you money, perhaps not worth it. Perhaps do what we did, write a letter to your GP, send it by post, requesting a written request for this test at ST Thomas. Include details/copies of the test at ST Thomas and explanation why you want to have the test, include a copy of the axis website see:

    and if you want include a copy of the BSCH guidelines on B12 and folate def‏ :

    Your GP will have to read it and reply in writing (within 10 days), which may help, particularly if you mention in your letter that you will pay the costs of the test. It also will help you having your GP's answer in writing; he/she will have to explain why he/she would refuse such a request.

    Kind regards,


  • Right, I never thought of writing to my GP. Good to hear re the 10-day time frame (gotta make 'em earn their keep!).

  • Just an update:

    I called the surgery re the cost of a doctor's referral, and the receptionist mentioned that they might be able to get a nurse test my B12.

    My main concern is the type of test performed (i.e. if it's just a plain serum vs the active test).

  • Hi, I could be wrong here as maybe things have changed in other areas/different surgeries. When I got my b12 tested it was serum b12 at the doctors which does not distinguished between active/inactive. I had to pay privately to get active test and mma to try and get myself a diagnosis.

  • Thank you, Leanneta. This too is my main concern, but I'll ask the GP when she rings. If it's the old test, then I'll ask for a referral for a private one.

  • Yeah definitely do that. When my active b12 was checked it was 29 out of a range of 25 to 165. My serum b12 was 236. My doctor kept telling me it was fine as was not clued up on active test. This is another obstacle to overcome in getting them to see there is a Prob. Make sure u also get your ferritin, folate checked as u also need these to be in a good range too

  • Dr has agreed to a serum B12, so will just see what happens. She did mention that if the results weren't good, they'll do the active B12. But she does seem ok with referring me for a private test, if need be.

    She doesn't sound to clued up on B12, with all the tricky nuances involved during testing, so will expect to go it alone after the serum test.

  • I think your doctor has got it wrong. As far as I can see, where the Active B12 test is most useful is in cases where the serum B12 shows a value within "normal" range but the patient has symptoms. That would typically be a serum test result in the 200 - 500 range which few GPs are going to regard as not good.

  • Perhaps print for her and post, or, give to surgery reception, the new British Society for Haematology Guidelines for the diagnosis and treatment of Cobalamin and Folate disorders:

  • Thank you, Marre. Will sit down and take a look at the updated guidelines.

    Some members here mention getting my folate & ferritin checked (as well as B12). Is there a gold standard test? Or will any one do? I don't want to waste money on tests that are bunk (if you know what I mean).

  • Yes bog standard tests serum folate and ferritine. B12/ folate and ferritine are all separate vials of blood, if tests if done at surgery. If privately they can be done together in my experience and expensive I did anaemia profile once at , it was £85, - (2007).

    This one is not terribly cheap either ( ) , will your GP not test for you? They are normal tests to do with B12 treatment.

  • Right, will do that.

    Kinda related to B12 is Vit D. Does anyone recommend the City Assays Vit D test? Linky:

    It's cheap for me, plus I can do it at home.

  • That vit D test looks good enough to me, and your GP must accept those results as it ist an NHS lab, it seems. No I have never used it, but may in the future, Marre

  • Well, just been off the phone from the PAS charity, and I am frankly quite disappointed in the advice (or lack of) given.

    I asked them if they could mention the common markers of PA in bloods, and the person basically drew a blank. They didn't mention ferritin/folate levels, and I asked re the MCH levels (which is actually printed in the latest PAS testing guidelines PDF), and again, the person said that this didn't matter.

    Quite appalling advice, and could potentially put people off getting a possible diagnosis.

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