I recently asked a question about testing for B12 if you take a supplement. The answers seemed to suggest you should stop supplementing for between a week and 5 weeks before testing. The answers raised some questions in my mind. Is the idea to take B12 supplements until your B12 gets to a reasonable level and then stop? Or do you take it all the time to maintain B12 levels. If the latter would in not be sensible to take the test perhaps 12 hours after taking the supplement to see how much B12 was active in your body?
I have also read contradictory advice on when to take the B12 supplements - one site said it must be with food and another to take it at least an hour away from food.
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SnowdropB
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The taking of B12 supplements is sometimes due to diets with insufficient B12 in them. Classic examples being at least some vegetarian and vegan diets.
In such cases, modest supplementation might be required. However changes to diet could sometimes remove that need.
However some people suffer from reduced ability to absorb B12 even when there would otherwise be sufficient in their diets. In such cases long-term supplementation may well be required - whether injected, by mouth or any other form - or combination of forms.
B12 processing is complex and simply measuring B12 in the usual blood test does not really say very much. And it is very dependent on recent supplementation (if taken). That is why there is now the Active B12 test. (Though that too requires stopping supplements for some time.)
I have looked at this site before and others. I gather that the Active B12 test is only available in London and it is hard for me to get there. My doctor says I do not have a problem, ie I am at the very bottom of the normal range. My underlying problem is that I have difficulty getting my T3 up from the bottom of the normal range without my T4 being well above the normal range. I have read on this site that B12 helps the conversion. Surely that depends on the level of B12 at the time? Or am I looking at this too simplistically? Is a normal blood test totally useless?
Don't make any assumptions, but call or email them to check. And yes, I do realise that this test has a significant cost.
Rod
Yes, in general the normal test is totally useless, other than for picking up people who have got to a point of severe deficiency. The reality is you can be B12 deficient at ANY serum B12 level, because (a) the test is flawed, and (b) B12 has such a complicated pathway to travel to get to tissue level, which can go wrong at numerous points. B12d.org believe that people should be treated on signs and symptoms, have a read of this:
I am taking 1000ug of Health Aid B12 (the less good one) in tablet form. I have been taking it for a couple of months. It does not seem to have helped much. My main symptom is tiredness and poor conversion of T4 to T3. It has not helped ether so far. I am thinking of trying the Jarrow B12 1000mcg lozenges. What do you think?
May I ask what your actual B12 level was when tested, you say it was right at the bottom of the range? What did your doctor say about it? Also, did you have folate, iron/ferritin or vit D tested? All these things can affect conversion.
I usually hesitate to recommend supplements, as many people would be better off on the injections (as long as they are given frequently enough).
Hi I've just today been put back on having my b12 injections.It doesn't make a difference where you live your doctor should test you.I'm also at the very bottom of the results table I feel so ill it's unbelievable. I know it's very hard for your body to absorb vit b12 I also know even with injections you only really get a couple of "good" weeks good luck if you take 1000 mg of vit c tabs daily this helps u absorb vit b12
Hi I'm not sure as I'm so confused of late I didn't ask! I just know that the nurse was concerned that all of my symptoms and results together weren't right,sorry I just know simple facts
Sorry Mummy5, I meant to reply to SnowdropB rather than you, technology malfunction! I'll repost my comment. Just read your comment, it's good you're back on the injections. But why were you taken off them? Treatment is for life usually. How frequently are you having them? When it comes to B12 you need good top end of the range folate and iron to get the most from your injections, so please make sure these are tested and supplemented if necessary. H x
Hi hampster1, I had my 6 weeks check 3 years ago after having a baby and the nurse took me off my injections, nice of her really! I had to have them every four weeks but this time my new doc wants me to av em every 3 months
Stella, I really don't understand, a nurse stopped your injections 3 years ago? Do you have Pernicious Anaemia? If yes these should never ever have been stopped. Go back to the new doc and insist on the loading dose again (6 injections over 2 weeks), don't just go straight onto 3 monthly. The nurse taking you off the injections would have put you right back to square one, something very similar happened to me which is why it makes my blood boil. H x
I'm going to ask the nurse on Monday when I go for my jab hopefully I'll regain a little of my memory back it's got to a stage that I'm slightly slurring the odd word every now and then :/ at the time it was pernicious anaemia yes
There isn't a cure for PA, you need injections for life. Insist on proper treatment including the loading dose, and a letter of complaint would be in order if you don't get it. On what planet does a nurse decide your treatment, especially one who clearly knows nothing about PA?
Point out to the new doc that you are in your current predicament symptom-wise because they withdrew your life saving injections.
The NICE guidelines for treating PA are here, bring a copy along:
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Can we talk about diet and supplements please? 
Vitamin B12 "normal" and /Serum Folate low
Ferritin, B12 and folate results 
Advice please - Are levels low enough for nhs help or should I buy supplements? 
