Pernicious Anaemia Society
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Help deciphering blood results please!

I finally decided to have a private MMA test at St. Thomas' in London because of my symptoms and was convinced that I had low B12. Anyway it took nearly two weeks to get the results and it seems my results are all within range except for

Active B12 (HoloTC) which says >128 pmol/L (reference interval 70-108). I can't get an appointment with my GP for a week and I just wondered if anyone knows what this means. Is it good or bad and could it account for how rotten I'm feeling?

I would be really grateful for any help from you knowledgeable people on this forum.

Thanks in advance

15 Replies

Thank you for your quick reply. No I don't take any B12 supplements but am taking Folic Acid 5mg a day because a recent blood test showed I was deficient. Would that make a difference and also do you know if high active B12 can make you feel as bad as having low? It's all very confusing!

Thanks so much


Thank you for replying again. I've only been on the folic acid for 7 weeks and my doctor has given me a prescription for 4 months.

I don't know why I got deficient in folate as I have a good diet and eat lots of green vegetables, particularly broccoli.


it does suggest that B12 isn't the problem and possibly folate may be the issue. Have you noticed any improvement in symptoms since you started taking the folate?


Sadly not. I also can't work out how I ever managed to get deficient in folate as I have a very healthy diet and eat loads of green vegetables.

Thank you very much for replying.


which would suggest an absorption problem - haven't re-read previous posts so apologies if I have already asked this - but have you been tested for h pylori, coeliacs and other problems - think you also mentioned in early post that you were having iron absorption issues - which would also suggest looking for an absorption problem.

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Thank you for taking the time to reply again.

I haven't been tested for h pylori but I was negative for coeliacs.

I actually have too much iron so have blood letting every 3 months to get transferrin saturation under 50%. I have one faulty gene that predisposes me to iron overload, but apparently you need two faulty genes to suffer from full blown haemachromatosis.

What would you suggest is the best way forward for me.

Thanks again for your help.


not a medic and HU isn't a substitute for good medical advice though I know that can sometimes be hard to come by.

an absorption problem isn't really going to explain the drops in your blood levels for B12 but is probably worth looking into in relation to the folate levels.

Do you know if you have any other genetic mutations that might affect B12 metabolism?


I know you're not a clinician but I actually think the people on this forum seem to know an awful lot more about B12 than any doctor I've spoken to.

I only found out about the faulty gene a couple of years ago and I do not know anything about which mutations would affect B12 I'm afraid. If you know, perhaps I could ask to be tested for them.

Thank you again.


This paper mentions a number of genes that affect the metabolisation of B12 in Table 1

some mutations, as Hidden says, will have serious consequences from birth but I don't think that is true of all of them. Some look as if they may be involved in PA itself and they are affecting different phases in the process.

Unfortunately B12 cuts across the way medicine traditionally defines specialisms and it is a vitamin - not an area that general practitioners get a lot of time on in their studies, which means that it is rare to find a medic who has much knowledge of B12 unless they have been specifically touched by having problems with metabolising it themselves, or a close family member does.

The article is talking about how B12 is metabolised so might be useful to your doctor in undestanding B12 anyway.

There is a lot of information on the PAS website - which has a section specifically geared towards medics but I don't know if it covers looking at genes - this is something that is used much more in medicine in the US than it is in the UK and even in the US there can be a tendency to latch on to specific genes and a tendency to not fully understand the difference between dominant and latent genes ... dominant = you have it you have the condition, latent = you have it but needs other factors to trigger (bit simplistic).


At the end of the day however, it sounds as if you actually metabolise and excrete the B12 that you are being given really quickly and probably need it more frequently as a result. The amount that is put in is about 3 years worth of B12 but on average most of it is lost in the first 24-48 hours.

It doesn't really explain what is going on with folate - think you had chemo and some chemo can adversely affect folate .... but not sure how long that effect would last.

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Thank you for your reply. I was lucky enough not to have chemo so the folate deficiency must be due to something else. Also I don't take B12 supplements or injections so only get what is in the food I eat so I'm very confused why the active B12 is so high. I don't suppose the GP will know so I'll maybe see if he will refer me to see a specialist.

Thank you for taking the time to send such a detailed response.


thanks for clarifying on the injections - thought you had been on B12 shots - mis-remembering.

high B12 isn't necessarily something to worry about but it can cause functional deficiency in some people. Is it just the active B12 that is high or was the serum B12 also over the top of the range? Generally active B12 accounts for 20% of the B12 in your blood. If the ratio is significantly different then it probably does point to something (genetic?) going on with the metabolism of B12. If serum B12 was also high then there are a few things that can cause raised B12 that may be worth looking into.

This paper discusses some of them


Yes, the B12 serum result was 391 ng/l (187 - 883). Thank you for sending that link. I have to say I'm reading it but it kind of goes over my head a bit! If you were me, what would you ask your GP to do to follow up my blood result?

Thanks again for your help


if you have a good relationship with your GP then be honest with them about this forum and share the article - it really is a medical article - I struggle with it a lot - and may be difficult even for medics who aren't involved in nutritional and gastric disciplines. say that table 1 suggests some genetics that might be involved and ask about consulting or being referred to a relevant specialist.


Thank you so much, I'll take your advice and let you know how I get on!

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Thank you for your help


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