B12 deficiency - when to test - Pernicious Anaemi...

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B12 deficiency - when to test



I've been suffering with a list of symptoms as long as my arm that the doctors haven't diagnosed a cause for so I had a hair sample test and it highlighted a b12 deficiency. Without looking into the problem I decided to supplement with 1000mcg lozenges daily for about a week to see if it worked and I immediately felt my symptoms improve. The remarkable response to supplementing made me look further into the subject and I now realise how severe the impact of b12 deficiency can be - I read the book "Could it be B12" and was shocked to see all of my symptoms staring back at me from the pages!

My doctor agreed a b12 test but he said that because I have supplemented for a week already I'd have to wait a month to do the test. Is this the case? I can't find any information on how long it takes for b12 to leave the system anywhere and I'd like to get the test and get back on it since I am beginning to feel unwell again since stopping.



18 Replies

Your doctor will only do the standard blood serum test which is useless so I really don't see much point. You have already proved that you have a B12 deficiency by your reaction to the supplements and to stop taking them now would be counterproductive.

I read this recently but I can't find it now - about 2 months I think.

You obviously can't go that long because you risk permanently damaging yourself.

I just read the book by Sally Pacholok with a forward by Dr. Joseph Chandy (they seem to be the authority on this) and they say the serum b12 is the gold standard and that anything less than 500 needs agressive treatment. they also say not to supplement until you have had a test as you won't know how deficient you are and how to treat it.

So my question really iss about how long to leave it until the b12 I have ingested leaves my system but i suppose that is a question that raises more questions such as how much b12 was ingested and how deficient I was in the first place!

Poppet - I have been suffering symptoms for about 18 months. Only mild in comparison to some but still very annoying so I'm thinking a few more weeks won't hurt? it is just difficult to keep out of the supplement cainet knowing it makes me feel better!!!


Hi jason1970 ,

I think it is very different per individual how quickly B12 levels drop, some hang on to B12 much longer than others, some end up with much higher serum B12 levels from the same B12 injections than others. It all depends on how deficient you were to start off with, what the reason is for that and what if any recycling of B12 still takes place. My daughter stayed off B12 injections for 7 months to then be deficient at tissue level (Active B12 test low, MMA to high). Her serum B12 dropped from 350 to 230 in that time, but I expect it will be very different per person. 3 to 6 months seems to be average for most required to be off B12 supplements before its worth testing (Active) B12 again.

Kind regards,


jason1970 in reply to Hidden

Thanks Marre,

My problem is I have no idea how deficient I was in the first place as it was a hair sample which some say isn't a good test anyway. My bloods are ok as I was tested for something else so the G.P. says it isn't likely to be pernicious aneamia and the fact I felt better after using b12 lozenges says I am absorbing it. I have been on Omeprazole for 8 years so I suspect that it is the cuplrit with low acid levels causing malabsorption and normal dietary levels of b12 not being enough resulting in deficiency.

I only had 9000mcg in 7 days using lozenges which I stopped a week ago and I'm already feeling crummy again.

Just really don't know whether to start chomping b12 or wait for a test that might not be accurate and end up notgetting treatment...

Hidden in reply to jason1970

I believe in waiting and getting all investigations done first before self medicating, because a right diagnosis now will give you (hopefully) the right treatment (for life). If you get no where after you've had all possible tests then you can self medicate, but this is a decision only you can make. I can not say I have a wonderful experience with my initial GP, it took long to get diagnosis and then 5 years to get more frequent B12 etc for me, one daughter was put quickly on B12 injections, the other it also took a year from initial to low serum B12 to then eventually for her to get injections, so its not a quick option. Self medicating is the quick option. Marre.

jason1970 in reply to Hidden

Hi Marre,

Thanks for your comments.

I am on the fence about this. I just don't know if it is wise to wait because my doc isn't up to date on the subject.

Engels made a good point about intrinsic factor (IF). My doc said I clearly have enough of it as I am getting relief from taking supplements, however, sublinguals don't need IF so that isn't a well thought out assumption.

Based on this he's just going to give me supplements anyway until I get a test that measure IF - like I said he brushed off the idea of injections without a second thought.

I'm of the opinion that it's most likely to be an absorption issue as I have been on acid suppressants for 8 years which is a major cause. My blood count was fine so it isn't PA.

If I could just find out how long it takes to raise blood levels based on my recent intake of 1000 mcg a day for 7 days I would know whether testing inside a month would be worthwhile. I cannot find an answer to this question anywhere.

engels in reply to jason1970

There isn't an accurate test for IF and you can't diagnose or rule out PA from a blood count.

The treatment for B12 deficiency is the same regardless of the actual cause - take plenty of B12 of whatever sort and by whatever means works for you as an individual. And by works I mean relief of symptoms, not figures in a meaningless blood test.

jason1970 in reply to engels

Thanks Engels. I'm thinking like this now. I'll just crack on with the sublinguals at high doses.

Hidden in reply to jason1970

There is this research paper that clearly shows up take and what ever storage still happens of B12 so different per person, see:


"Variation between patients makes it impossible to anticipate the duration of effect of a single injection of one of these drugs in any patient."

There is no gold standard test for B12 deficiency. Probably the best test is the Active B12 test which is not available on the NHS but which you can get privately at Guys/St Thomas in London provided your GP will give you a referral. The blood serum test is a very crude tool which does not determine how deficient you are nor can it be used as a guide to how much B12 you need. Your symptoms are the best guide to how much B12 you need.

It seems pointless to me to make yourself ill again by stopping supplementing just to have a useless blood test, the results of which your GP may use as an excuse to refuse treatment if, as is quite possible, your B12 level falls within the "normal" range. Dr Chandy and Sally Pacholok may well treat at levels below 500 but they are very much the exception. The "normal" range varies between labs but is usually something like 150-900 and most GPs will not treat unless the level is below the bottom end of the range.

jason1970 in reply to engels

Your advice is much appreciated Engels and thanks for the clarity, I misread and they actually said there is "no gold standard" too - apologies. It's just that they advocate treatment for results <500 as you have said already but have also said to not self treat.

From the conversation with my G.P. he was fairly sure I had enough intrinsic factor to absorb b12 since I felt the benefits the same day and he was also skeptical about injections. So I fear he wouldn't treat me properly.

Does this lack of concern towards the problem mean I'll just have to use lozenges at trial doses? Could I be putting myself at risk by not getting a test and therefore getting proper treatment?

When you say you've used lozenges do you mean sublinguals which are held under the tongue or oral tablets which are just swallowed? What form of B12 were they?

jason1970 in reply to engels

Hi Engels,

Jarrow Methylcobalamin B12 - can be chewed or dissolved in the mouth.

One if the reasons I asked is that you mentioned Intrinsic Factor which only comes into play for processing B12 from food in the stomach. The point of sublinguals is that the B12 is absorbed directly via the membranes in the mouth bypassing the digestive processes which require Intrinsic Factor. In other words, the fact that you have responded if you have used sublinguals does not mean that you have sufficient Intrinsic Factor to absorb B12 through your stomach.

I don't know why your doctor should have doubts about injections when they are generally recognised as by far the most effective treatment.

I see your point.

What would you do, wait a month and test or just start on the b12?

Like I said if I don't come back below 200 I doubt he'll inject anyway but I'll at least have a clear idea of deficiency levels.

Thanks again.

I would just take the B12 but I know others will disagree and will argue for you to wait and allow your doctor to do more tests. Those who have had a positive experience with their doctor will tend to argue to wait, those like myself who found their doctor to be next to useless will probably agree with me that you should just get on with treating yourself. You are fortunate in that you appear to have found a form of B12 that works for you at the first attempt. I found that methyl sublinguals didn't help me at all.

The other thing you need to look at is the Omeprazole if you are still taking it. I have no personal experience as I have not suffered any stomach problems but I do know that doctors often prescribe Omeprazole and the like without carrying out proper tests. The symptoms of low stomach acid and high stomach acid are virtually identical but very rarely is stomach acid tested. There is quite a lot of discussion about this on other threads which I would advise you read if you have not already done so and perhaps someone else will be able to offer more advice.

Research done back when there was no treatment and people died of the illness showed that although many had the minor symptoms for years previously, they usually did not attend the doctor until their symptoms became, for want of a better word 'progessive.' That usually was difficulties in walking, weakness, numbness, tingling, partial paralysis - and on a permanent basis. From the patients recorded it then took between 3 months and 24 for them to die of neurological degeneration. And they know this because they examined the damage to spinal cords post mortem.

Nobody can tell you how long to wait, because no one knows how far your illness has progessed. But there are, obviously, risks. Which is why UKNEQAS are alerting that people with neuro symptoms and normal b12 should still get treatment immediately.

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