Pernicious Anaemia Society
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Result of 'active B12 test'

Hello All. I hope that someone out there can help me with interpreting the result of my 'active B12' test which I received today. I am a bit worried as it is way OVER the normal range and according to the internet this can mean all sorts of horrible things like liver cancer, hepatitis, kidney disease etc. What is not clear from what I have read is this: do these high B12 readings refer to both kinds of B12 tests - sarum and 'active'. I am quite confused. Anyway my 'active B12' result as follows:

256.0 pmol/l (25 - 165)

This follows a negative IFA test last week. My sarum B12 test indicated a level of about 2000. My main question is this: can this high active level of B12 be caused by the very high doses of sublingual B12 I have been taking for months? Or do I really have a serious liver problem? Finally, if my active B12 is that high does it mean I don't have a B12 deficiency at all? How then to explain all my classic B12 deficiency symptoms? And how is it that taking these supplements have greatly reduced these symptoms? Many thanks in advance!

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Have you been injecting B12?

No. Just high doses of sublingual.

Hi Frank77.

Yes, taking high dose sublinguals, nose spray or tablets can result in serum B12 and active B12 results that are way over the top of the reference range.

This does not mean that you do not have B12 deficiency...the high levels are a result of the high dose sublinguals and it's likely that if you stopped supplements, your B12 levels would drop again.

Taking the supplements will have reduced your symptoms because you are addressing the original deficiency.


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Hello Foggyme. Thanks for that: a great relief to hear that these high values are probably due to the high sublingual I have been taking. But now for me it is really back to the drawing board. I have done the tests that have been recommended on this site - serum B12, IFA, active B12, folate. My symptoms responded well to the Solgar B12 sublingual drops I started taking in January, but I am still not 100%. Chest pains though disappeared with two weeks. Yet now I am told that I have high levels of both sarum and active B12. Simply don't know where to go next. I still have some brain fog and balance problems, notwithstanding my high B12 levels. I was planning to have B12 injections soon because of this. Now i really don't know... Any suggestions would be gratefully received.

Hi Frank77.

High serum B12 or active B12 levels, whether due to oral supplements or injections, do not correlate to relief of symptoms. In other swords, B12 levels cannot be used to assess how effective treatment is once supplementation has started.

Flooding the gut with high levels of B12 can enable some B12 to be absorbed via passive absorption, and this is obviously what's happening, in your case (though this doesn't work for everyone).

The first thing is that recovery from some symptoms (especially neurological ones) can take some time, for some many many months. And you are early in the treatment process so it may be that recovery will continue, over time.

The second thing is that in the UK, the prescribed treatment for those with neurolgical symptoms (which you have) is an intensive regime of B12 injections (injections every other day until no further improvement). Sublinguals or B12 tablets are not the recommended treatment.

And here's a third thing...just because your B12 levels in the blood are high, there's no way of knowing if the B12 is getting from your blood into the cells, where it's other words, what's called functional B12 deficiency (those with functional defieiceny report that they have to maintain extremely high B12 levels in order to get and keep well - the highest I've seen here is 5999 - the highest the referenance range would go). you have a functional B12 deficiency - no idea. Are you getting enough B12 from the sublinguals so that your body can repair properly. No idea. Is your B12 deficiency being under treaded. No idea.

So, based on the fact that you had - and still have - neurolgical symptoms and that B12 injections are the recommended treatment in the UK, then if it was me, I'd be looking to get the prescribed treatment (since it's the one proven to work) rather than sublinguals (which may or may not work). In short, where neurolgical symptoms are concerned, why take the risk 😉.

If it was me I'd want intensive every other day B12 injections - the treatment as per the BCSH Guidelines for those with neurolgical symptoms.

Here's a link about issues to do with oral or sublingual supplements:

b12researchgroup.wordpress.... (Serious Caution Note about the use of Oral and Sublingual B12 Supplements)

Here's information about B12 safety and long term treatment for those with neurolgical symptoms: (B12 Treatment Safety / Long Term Treatment for neurological symptoms).

And here's some information about serum B12 test (by extension, the same is applicable to active B12 test too): (Problems with Serum B12 Test) (Testing B12 During Treatment)

Something else that might be useful: (Misconceptions About B12 Deficiency – Good to Know Before Seeing GP) (B12 Deficiency: Neurological Symptoms Can Present Even When B12 is ‘In-Range’ and Without Macrocytosis (large red blood cells) or confirmed PA Diagnosis)

And an excellent research paper: (Haematologist B12 Treatment Review March 2017 – Includes Advice No Reason to Advise Against Self-Injection/More Frequent B12 Injections)

Good luck


P.s. and just in case you haven't seen them, here's a copy of the BCSH guidelines for the diagnosis and treatment of cobalamin (vitamin B12) and folate disorders: in Haematology (BSH) Guidelines: Treatment of B12 Deficiency and Folate Disorders)


Fascinating. Thank you so much!

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Can take 12-18 months to get better...if you get injections and then the MD stops them...restart sublinguals! MDs usually undertreat and stop too soon - plus once you stop you’re on your way to deficiency symptoms again. Happened to me 2 yrs later at serum of 743!

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Today I looked for Hydroxocobalamin in local (Moscow) pharmacies, but impossible to find here. It seems that cyanocobalamin is the local B12 injection of choice, so to speak. It is sold in 500mg ampules. Also got some needles (0.6mm x 30mm). So I am almost ready to inject myself: this will be a first so slightly nervous. I did ask in local clinic if they would do it for me - for payment - but they refused as I do not have a doctor's 'order'. So can anyone tell me if this cynanocobalamin will do just as well as the hydroxocobalamin? Many thanks in advance!

Yes...cyanocobalamin will work just as’s the cobalamin of choice is some Countries (i.e. America and some in Europe). Cyanocobalamin needs to be taken more frequently than Hydroxocobalamin (1 monthly as opposed to three monthly) - though that’s the prescribed 'one-size-fits-all' regime (required frequency of injection differs per individual - best to try and have the next jab before symptoms come back rather than after they've arrived - though finding a doctor who understands and will accommodate that is often no easy task - whatever country you live in 😉).

Good luck.

many thanks!

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I would also suggest you have your Folate and Vit D levels checked. You may be deficient/low in either or both of those, which could explain some of your symptoms.

Folate is necessary for your body to utilize B12

Hello JMN2017. I had my Folate checked a few weeks ago and it was 40.1 (3 - 17). So I presume that this is quite high? I have not checked Vit D but have been taking supplements of Vit D and Iron for the past 3 weeks so I imagine that this might skew any analysis?

Hi Frank77

That's interesting that your Folate is so high. I believe high folate can indicate B12 deficiency so it would tie in with Functional B12 deficiency, as Foggyme has suggested. It would explain why you still have symptoms.

MMA and Homocysteine tests could be of value. If you have Functional B12 deficiency, with it not getting into your cells, I believe these tests are likely to be high.

Certainly, you should be looking further into this, as already suggested.

Good luck and keep us updated, eh? ;)

Thanks for that! I know nothing about this high folate angle ... will try to find out more. Do you suggest I have these MMA or Homocysteine tests? What can they actually show and can they actually point to a cause of B12 deficiency that can be treated?

hi foggyme , i have severe migraines due to excess nitric oxide -after taking a supplement called pine bark extract -picnogenol for 1 month 4 years back for chronic pelvic pain/endometriosis . My b 12 levels were low at 180 pg/ml and methyl cobalamin shots cured 50 percent of my migraines . My neurologst wants me to try hydroxo . I live in india and Hydroxo is unavailable here . My vitamin b 12 levels after 20 shots of methyl was 3100 pg/ml - after the sixth shot methyl cobalamin was ineffective -i would like to know why ? b 12 not entering the cells after the 6 th injecton . i;m planning to get activ b 12 test done here.can you pls recommend a neurologist in UK who could help me with hydroxo -IT 'S URGENT AS I'M SUFFERING A LOT

Pinkypop. Know it's a bit confusing but once again, you've replied to a six month old posts...and as Gambit62 has explained (and myself, in response to a PM I received from you), people rarely return to posts this old.

Think Gambit also explained why we are unable to receommend consultants in the forum.

Please can I also mention that there is little to be gained from posting the same question in multiple places in the forum (some as replies within other posts that are very old). Doing this means that forum members potentially have to answer the same question many times over...and any replies to you are scattered all over the forum, instead of being collected in one place (confusing for you).

I echo Gambit's comments that if your neurologist in India wants you 'on hydroxocobalamin', then they will be the best person to prescribe it or suggest a source where you can get it.

And to answer one of your other questions, your normal MMA result shows that B12 is getting into your cells, where it's needed.

See you’ve also put up a new post with your question so hopefully, others will reply to you there too.

Frank77 - if you're still active in the forum (😉), please ignore notifications in relation to these replies. Your post is old now so going to turn-off replying.


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