Pernicious Anaemia Society
16,269 members11,332 posts

B12 Really high a year after injections were stopped Help please

Hi please could someone advise if possible please ? I haven't been diagnosed with PA but was receiving B12 injections for pheripheral Neuropathy and they helped 👍 My GP was really good even though my blood test was in range she said we can give you injections it's not about results :) ..anyway she retired last year and when my bloods were taken shortly after my other GP rang and said NO more injections as B12 over 2000 .. So since last MAY NO more injections and NO supplementing I haven't been too bad symptom wise as I paid Biolab for my other B vits to be checked and was low B1 B2 B6 which I believe is because I'm a coeliac and don't absorb very well ? ..Anyway I will get to the point ... A year on and my bloods are still showing over 2000 B12 with no supplementing at all , I paid again Biolab for a homocysteine test and it came back at 9.7 top of range is 12 .. I didn't have the MMA and I think this may have been a mistake ? ... My GP sent my results to a haemotologist who now wants bloods repeated and my GP is worried I have something sinister going on ??? My FBC was high in a few places :(

I've been worrying myself silly about polycythemia Vera :( .. I also found a year ago I am hypothyroid and take thyroxine ... My palms are always red but my liver function was ok .. Sorry for the long post but do you think I should have the MMA test done ? And where is the best place to do this ? as not sure Biolab does it ? And would I need MMA and homocysteine done together ? As already had the homocysteine .. Many thanks in advance Take care Lynn xxxxxxxxxxx

22 Replies

You say you were diagnosed with PA. Were you actually diagnosed with Pernicious Anaemia, with tests for antibodies to Intrinsic Factor and/or Gastric Parietal Cells. Or were you given a different reason for having low B12?

If you do have PA then you need injections for life. Download my summary document - - plus the BMJ article linked to therein. On page 4 of that paper it says...

In irreversible cases, for example, pernicious anaemia, the

treatment should be continued for life.


Hiya thank you for your reply .. No I wasn't diagnosed with PA ... I was given the injections to help the neuropathy .. Just wanted to know if it was a good idea to have the MMA test as I have had the homocysteine blood test .. Need to find out why my b12 is still so high after a year of no supplements ? Thank you for the info xxxxxxxxxxxx


If you don't have PA, or any other absorption problem then that may explain why your levels are fairly high.

The liver excretes B12, via the bile, into the top part of the small intestine. There it encounters Intrinsic Factor (IF) and the two bind together. Further down the small intestine the gut wall has cells that grab hold of IF and drag it across and into the blood - carrying the B12 with it.

This process (enterohepatic recirculation) is very, very efficient, so the body loses very little B12. Most of the processes that require B12 also recycle it, so only tiny amounts are used up. That's why the average human needs just 6 ug (6 millionths of a gram) of B12 a day. If you're eating a diet with enough meat/fish/dairy then you should be consuming that sort of amount daily.

If you did have PA then your body wouldn't make IF and the B12 that you eat, plus that excreted by the liver, wouldn't be absorbed.

An MMA test would tell you if your symptoms were down to low B12. But it doesn't sound like it.


Thank you so much for the reply it does make sense 👍 I kept to a high b12 diet after the injections being stopped and no supplements .. Do you think it's pointless having the MMA test done ??? The homocysteine was 9.7 and top of range is 12 Biolab said if homocysteine high this normally means b12 defeicent ? It's all complicated when I was getting injections my b12 was about 700 but GP said we will ignore that and treat with b12 for the symptoms ! The GP now said keep off foods that are high b12 red meat etc and see if b12 lowers ? Thank you for your help xxxxx


Do you think it's pointless having the MMA test done ?

Not really. If it's high then you'll know that you have a functional B12 deficiency. If it's not then you'll be in the same position as many of us here - high B12, low MMA and hCys but still suffering from symptoms.


Hi Lynnwin, do you remember what your b12 levels were initially before starting b12 shots? My serum b12 level was 202 last year when I was experiencing neuropathy (burning feet, muscle twitches etc). Since then doctor recommended b12 sublingual supplements and my levels went up to 900 in 3 months. Since then I stopped supplements thinking b12 is in range and also experienced some relief in symptoms. But now my symptoms are back and my b12 level has dropped to 500.


Hiya my b12 was in range at 430 but I know that's too low for me and the b12 injections have helped before .. I haven't had a blood test this year for my b12 I do get small flare ups but finding magnesium oil rubbed into my skin seems to help 👍



I don't think I will show my gp this = it is rather vague when it comes to people needing more frequent injections!


Hello Lynwinn

Your high B12 levels may just be an indication that treatment with B12 injections has taken place. It can take up to two years, or longer, for levels to drop, post treatment.

In cases where B12 supplementation has NOT taken place, high levels of B12 can be an indicator of other problems. Perhaps your GP has this in mind and is simply being cautious.

However, if you do have vitamin B12 deficiency, treatment should not be stopped due to normal or high B12 levels, post-treatment with B12 injections. So... the difficulty is that your current GP might argue that you did not have B12 deficiency as your results were in 'normal' range. However, serum B12 levels have been proven to be inaccurate and can return false 'normal' or high levels. All the guidelines state that treatment should be based on symptoms and NOT on serum B12 levels. So, your original GP was RIGHT to treat your symptoms. It gets even more complicated...if you are symptom free at the moment, it is going to be difficult for you to ask your GP for B12 injections (i.e. for injections to treat symptoms that you currently don't have).

I think that your GP is wise to do more tests and it may be worth waiting to see if these reveal anything before you do other tests yourself. Your GP may be prepared to order extra tests, based on the results of the additional ones he is doing.

There have recently been discussion threads here about MMA and Homocysteine tests, so if you do a search, you should be able to find more information.

Some thoughts: you say that you were not diagnosed with PA but were given the injections for peripheral neuropathy. Did your GP ever investigate the cause of this? And did you ever have any other symptoms of vitamin B12 deficiency? Do you have peripheral neuropathy now? Are your low in any other vitamins, mineral, iron etc., as a result of your coeliac disease. If you are, this can present with symptoms similar to B12 deficiency. These are things you could perhaps explore with your GP.

I don't know anything about thyroid problems but I do know that there is a lot of cross over symptoms between B12 deficiency and thyroid symptoms. Perhaps it might be worth having thyroid tests again to check all your levels. I believe that it is not enough to simply test TSH levels. But perhaps someone with more knowledge will see this and let you know what you should ask for, or you could always post a seperate question.

I know it's very difficult not to panic when waiting for blood test results etc. I think many of us imagine the worst, even if we try not to! I always try to 'eat the elephant in chunks' and deal with things as and when they come along. Believe me, it's really good news that your GP is investigating. It means he's on the ball and is prepared to help you.

In the meantime, if symptoms of B12 deficiency return (I believe your are currently symptom free with no supplements for one year), then you could discuss this with your GP, with a view to re-commencing injections. If you need to do this, post again on here and there are many who can direct you to relevant guidelines which you could take in to discuss with your GP. It's worth noting that many GP's are not good at treating B12 deficiency / PA so, if necessary, you may have to become your own expert.

Sorry I can't be more helpful. Please try not to worry too much and post again if you need any more help.

Good luck. Let us know how it goes.


Foggyme thank you so much for the time you have taken to help me :)

Yes I was getting injections when my b12 was fine but the GP said we will give you them every 12 weeks to keep oh toppd up as these did help with the neuropathy ... I was diagnosed by a professor of endocrinology with neuropathy as my b12 was in my boots and instructed the GP to give injections which he did and then I stopped them myself as I felt fine and then she the burning sensations flared up my GP who has now retired ordered more injections even though my blood test was almost top of range :) ... It was last year after a blood test the GP said stop the injections as it was over 2000 which I didn't worry about as I was having the injections on a 12 week interval .. I think now after a year of no injections and no supplements and with my full blood count being over range it was me that put it in his mind about PV and the high b12 being a cause of something sinister :( ... And he agreed high b12 can be a sign of a sinister disease :( ... My bloods were sent to a haemotologist and he has requested more bloods .. I was defeicent in B1 B2 B6 which I still supplement ,this is most likely from coeliac disease as these vits are wheat germ etc ... I didn't have iron studies done and I believe they will be done next week ? My thyroid is OK been tested by NHS and private London bloods zinc copper magnesium ,selenium are fine :) and my homocysteine was 9.7 the top of range being 12 and the technician said being hypothyroid can cause a higher homocysteine and of course age ! I don't feel I need any B12 and my neuropathy much better :) My maim symptoms from low b12 was burning prickling all over my body and extreme tiredness where I was bed bound for weeks :( ... Thank you so so much for your excellent reply I really didn't know it could take up to 2 years for b12 levels to drop ? You would think GP would know this ?? On second thought doubt he has a clue ? Thanks again feel a little better now take care xxxxxxxxx

1 like

Ah you did have a low B12, with neurological symptoms! And when you stopped injections, the burning / prickling came back.

Best to just be aware that high B12 levels are simply an indication that treatment has taken place. If you get any of the symptoms back, just beetle off to the doctor and get some more B12, on a regular basis.

If you do get symptoms, please don't put up with them 'cause they're not too bad', as neurological symptoms may become irreversible if not treated. Ideally, the symptoms need to be gone completely (not just much better).

Hope you get some 'good' answers. Take care.

Post and let us know how it goes.


Thank you so much Foggyme .. I certainly will ask for more b12 if symptoms flare up again .. I do wonder if my neuropathy is kept under control by having the high B12 in my blood ? .. I was ill for 4 months with neuropathy going from one doctor to another trying to get well and spending a fortune on private doctors :( .. and in the end it was b12 such a simple blood test that no one thought to do apart from the Harley street endocrinologist .. Thank you so much for your time .. Keep well xxxxxxxxxxxx

1 like

Lynnwin...that happens to so many people! And yes, it may be the high levels that are keeping your symptoms under control (mine are always over 2000).

Just an you're having lots of additional tests, might it be worth asking your GP or consultant to test your for Pernicious Anaemia?

Take care.

1 like

Thanks Foggyme will ask for a PA test also when I was really poorly some years ago I did have the intrinsic factor tested and that was fine ..I will ask for PA test ..can I ask do you have injections ? Or just supplement ? Thanks again xxxxxxx

1 like

Hello again Lynnwin. Just so you know, PA tests are not always accurate: in about 50% of cases, I think. From what I have read in this forum, I believe it is possible to test negative but still have PA.

Injections: yes. Since 2012 I've been on 3 monthly jabs of Hydroxocobalamin, following a loading dose of six. Symptoms never fully resolved and like many people here, I found that this was not enough to for me.

In April, my GP stopped B12 injections due to high Serum B12 levels (ring any bells!): at that point, I arrived here and boy, have I learnt a lot!

Think that I was never give enough to begin with and certainly not treated by the regime intended for neurological symptoms!

GP has refused point blank to give enough B12 to get me well so...following what I have learnt here, I now self inject B12.

Currently doing 1mg Methylcobalamin every other day and supplement with Methylcobalamin lozenges and adenosylcobalamin lozenges for an extra boost when energy flags.

I have been doing this for about three weeks now: initially I felt much worse but am now starting to see some small improvements (sleeping better for the first time in many years).

I think it's going to be a bit of trial and error but I'll slowly extend the time period between injections to see what suits me best.

I also discovered (again after being here), that my ferritin, Vitamin D and calcium levels were bumping along the bottom of what my GP called 'normal' ranges: not good enough for someone with B12 deficiency, so I'm now working on increasing these levels, since I believe that this was making me feel much worse.

Getting more knowledgable about what's going on has made a real difference to me but I have to say, it's quite difficult having to do this without medical support! But I'll get there!

Good luck and keep well x


Hiya hope you see this post wasn't sure if to start a new thread ??njust got my blood results back again and are as follows my friend is pretty good with blood results and she thinks I may be anemic ? Still,trying to get to the bottom of a high b12 @ 2000 top of the range 700 .. NO,injections for a year and No supplements either was having injection s for nuropathy even though my b12 was in range .. But GP stopped them as so high ...

Serum iron 15.6 range (6.6- 26)

Serum transferrin 3.04 (2-0 -3.6)

Transferrin saturation 23% (15-50)

Serum ferritin 177 but no range for it :(

My folate in April was 17.8 (17.8-37.3

If anyone could give any insight that would be great I am also taking Levo for hypothyroidism .. Thanks in advance xxx


Hello Lynnwin. Away from home at the moment so not much info with me. Folate looks a little low, difficult to comment on serum ferritin without the ranges (mine was 14 in the range 10-240), not sure about the rest without looking up. Might be a good idea to post the results on a new post so that others can comment?

With respect to stopped B12 - if I was you I'd get together some evidence and go back to your GP to try and get treatment re-commenced. Treatment should not be stopped due to high levels - all the guidelines say this- high levels are simply an indication that treatment has taken place.

See what you GP says once he / she has seen the evidence.

Good luck.


Hi Foggyme thank you for replying I have now posted a new thread :) I made a mistake with the folate it should be 15 (4.8-37.3 ) my heads all over the place :(

Thank you for replying maybe some other members will comment ? Take care xxxxxxxxx

1 like

Omg GP stopped yours too :( grrrrrr they make me sooo angry .. Well done you for doing the injections yourself 👍 My vitamin D was adequate but I learnt a lot on thyroid uk that it needs to be top of range and since taking vitamin D I'm feeling better with my thyroid issues 👍's all such a fight to get well :( ... Will ask for the MMA and PA test while I'm at it might as well add what ever I can I was wondering about the halo test too ? ..catch up laters off to work now :( .. Take care xxxxxxxxxxxxx

1 like

High B12 levels in themselves are not a problem. However, they can be an indicator of a number of other of conditions - but if you have had treatment with injections then even a couple of years later that is likely to be the cause rather than anything else.

B12 is used in treating a number of conditions involving peripheral neuropathy - including diabetes, ME and MS ... and although some of the improvments may because there is also an underlying B12 deficiency the implications of studies are that this isn't always the case.

1 like

Thank you Gambit62 I had no idea the levels could stay high that long ? Foogyme did say the same :) you would think the GP would know this ???

Thank you for taking time to reply to me very much appreciated

Take care Lynn xxxxxx

1 like

Unfortunately B12 isn't really covered in medical syllabus so on one level the ignorance is probably only to be expected. Add to that a tendency to treat numbers following formula and some guidelines on B12 that make it easy to think that it is just a blood disorder and you have a recipe for disaster.


You may also like...