Thyroid UK
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Has anybody tried this Active B12 test?

I saw this posted by RedApple (thank you) and wonder if anybody has tried it. And if so, was it helpful? I thought the Active B12 test was only available in London with a GP referral? If ths is the real thing it would be great - no way I can get to London and no way my GP is going to refer me anyway, as my B12, though not great is 'within range'. Thanks.

Kanga x

17 Replies

Me again! :D

I haven't used it Kangagirl, but I have absolutely no reason to doubt it. As I understand it, it's exactly the same test that you might pay a much heftier price for if getting tests done through a private consultant from here

As it's very new, I don't expect many here will have bought the active B12 test kit yet.


Grrr - I posted a reply to your message RedApple, then managed to delete it!

After reading shaws post below, I'm now more confused than ever. I thought 'Active' meant active at cellular level, rather than Serum B12, which might make it seem as though you have plenty of B12 sloshing around your body, when in fact you are, or might be really deficient where it matters.

I did a bit of Googling and found this: (I think Biolab are pretty reputable)

This is an extract: (The caps are mine)

"The ‘Active’ Vitamin B12 (holotranscobalamin or holoTC) assay

‘Active’ vitamin B12 (holo TC) is the METABOLICALLY ACTIVE portion of vitamin B12. This assay measures holotranscobalamin in a form that can be taken up by the receptor-mediated process found in all DNAproducing cells [6]. The holoTC assay is the earliest and most sensitive laboratory marker of a negative vitamin B12 balance and gives a better indication of vitamin B12 deficiency than the previous commonly used markers'.

Further along it says this:

"Specimen requirements

Serum separator tubes (plain gel tubes - available from Biolab on request). If posted, samples must reach Biolab within 24 hours".

So although they do want it pretty quickly, it doesn't say anything about 3 hours, or that being what 'Active' means.

I don't want to contradict anybody, but I would appreciate any further thoughts or comments. I would really like to have the Active test, but it would have to be a home one - now I don't know what's right and what isn't (nothing new there! :-D )

Thanks again

Kanga xx


I had an Active B12 blood test on Tuesday at St. Thomas' so should get the results in about six days. When they say 'Active' it means that the blood has to be tested within about 3 hours, thus that is where the Active comes into the blood test.

I paid £18 for the test and had a referral letter from my GP although he had never heard of Active B12 before. I gave him details.


Hi Shaws,

As far as I can tell, the timing of the test is not the issue with Active B12. I don't pretend to be an expert by any means, so rather than try to explain anything myself, I'll just quote directly from the active B12 website.

What is Active-B12?

Three carrier proteins are involved in the transport of Vitamin B12 around the body - Intrinsic Factor (IF), transcobalamin (TC) and haptocorrin (HC).

When transcobalamin and haptocorrin bind Vitamin B12 the resulting complexes are known as holotranscobalamin (HoloTC) and holohaptocorrin (HoloHC).

Holotranscobalamin represents only 10-30% of the Vitamin B12 circulating in the blood but is the ONLY form of Vitamin B12 that is taken up and used by cells of the body, hence it's other name... ACTIVE-B12.

Here's the link to the full info


I sent a question to the people offering the test, tactfully asking them if it was 'the real thing' - as I had only heard of the one in London.

I had a reply from Paul Harris of Blue Horizon - I didn't realise it was one of their tests, or I probably wouldn't have asked, as I have had tests done with them before and think they are very good.

I asked him if he could tell me (us) the once and for all definition of 'Active' in this context - but now I'm hearing about the possibly added need for an MMA and Homocysteine test...where does it all end? Still begs the question of whether the Active B12 rest is worth having if you know you'll never get these further tests from your GP. Or am I being too pessimistic?


It's what the Phlebotomy Department at St Thomas' told me. Not an expert myself.


Hi shaws - I see while I was busy writing a reply and then managing to delete it :-D RedApple has found some info on Active B12.

I Googled it myself because I didn't think Active referred to the time between taking the blood and having it tested either, but I wasn't sure by any means. (See my reply to RedApple above, though from a different source).

I'm no expert at all, and I'm more confused now than I was before! I would be very interested to hear how your test goes when you get the result. Thanks.

Kanga xx


also just to 'remember' that if your B12 comes in the 'grey area' they will need to test your sample for 'methylmalonic acid' and they will ask for a further payment of around £88 (can't remember exact price but it was thereabouts).

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Hi, just like to mention there is a possibility on MMA and Homocysteine being low if you have a problem absorbing proteins. So it is possible this could be false. As you probably know pernicious anemia suggests you also could have digestive issues. :)


Hi nobodysdriving - do you have any idea what the 'grey area' might be for the Active B12 test? I thought I was in the grey zone with my regular B12 test - 409 going down to 365 back last summer, no idea what it is now - but of course this is 'in range' so anything I do will have to be without any help from the GP - no surprise there.

I was astonished it was even that high because everything else was on the floor and my diet is unintentionally terrible, so that's why I'm so interested in the Active B12 test.

I have bought some injectable B12 which is a mixture of hydroxcobalamin and cyanocobalamin (from a body building site - would you believe - :-) where the product has loads of very positive reviews, particularly with regard to improving the appetite, which is one of the many things I need to address). But I've seen so many contradictions about it having to be injected intramuscularly, then no, subcutaneous is fine, then no, you can do all kinds of damage injecting subcutaneously...then your liver might need detoxing for it to have any effect at all...that I still haven't plucked up the courage to self inject. Wimpy or what! I should pull my socks together and get on with it. :-)

The liver detoxing might be something that some bodybuilders have to do - the things they put their bodies through and the high doses they take of just about everything is pretty scary. Hopefully they are healthy in the first place though, and not suffering the trials and tribulations of being hypoT....

Kanga xx


Sorry can i just ask what you mean when you say "tested within 3 hours"...............3 hours of what?


Hi - not wishing to speak for shaws, but I would assume it means within 3 hours from when the blood was taken.


Kangagirl is correct. Three hours from when blood is taken.


Hi all,

We do indeed offer active B12 on some of the websites we have. Although forum policy dictates we don't self advertise, Kangagirl has kindly provided the link at the top of the post.

There are no special transport/storage requirements that the Lab needs so the usual postal envelope provided will do the trick. As always avoid posting over the weekend if you can.

Use the TUK10 voucher code and you will get £10 off, and we donate to the lovely Thyroid UK too. This site provides a microtainer (finger prick) but if you have no luck we can send you out a vacutainer instead.

email me paul.harris@bluehorizonmedicals if you need any further details and I'll be happy to help!

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Thank you for posting, Paul, and for the information. Credit should go to RedApple too for being the first one to draw our attention to the website offering the test - I only knew of it from her original post.



Hi Kanga. It would be a good idea to join the Pernicious Anemia site on may get some valuble answers there. :)


Hi buggles - I already joined the PA site a while ago, but thank you for your interest :-)

Kanga xx


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