GP stopped B12 injections: Hello, I... - Pernicious Anaemi...

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GP stopped B12 injections

Irismay profile image

Hello, I wonder if anyone could help me please. My GP prescribed b12 injections every 3 months about 5 years ago because of low levels but the cause was never given. Over a year ago following a blood test my b12 levels came back over 2000 so my GP stopped the injections. Last week (Over a year later) I had another blood test & my b 12 level was 1600. I wondered how long it takes for b12 levels to return to normal? Thank you for your help.

16 Replies

I think your stores run out between 3'-5 years. Depending on if you are now able to absorb and store in your liver. It appears very high still if you've not had injections for a year. Also the most important thing is how you are feeling.

Irismay profile image
Irismay in reply to Nackapan

Thank you very much for your help. I am feeling pretty rubbish hence the recent blood test, tired, very bad brain fog, dizziness, gastric problems. GP says she will recheck levels in 6 months. Thanks again.

Gambit62 profile image
Gambit62Administrator in reply to Nackapan

Nackapan, please note response below.

If the problem was that stores of B12 had been replaced and were being run down then B12 levels would be in the normal range already.

Gambit62 profile image

Irismay - serum B12 isn't a test that can be used to manage B12 absorption problems and the BCSH standards on the diagnosis and treatment of cobalamin and folate disorders state that B12 injections are for life and testing isn't necessary after treatment has started.

I'm guessing that you have all the symptoms of B12 deficiency and have had them for quite a long time. Serum B12 only measures the amount of B12 in your blood and doesn't tell you anything about what is going on in your cells which is where B12 is actually needed. Significant numbers of people seem to react to high serum B12 levels by making the process that allows B12 to pass from blood to cells a lot less efficient, meaning that they need much higher levels of serum B12 for enough to be available in their cells so can need levels well over the top of the normal range to function post loading shots - this isn't something that is really covered in the guidelines mentioned above.

Unfortunately this reaction also seems to slow down the rate at which B12 is removed from the blood by your kidneys meaning that it takes a very long time for levels to fall back into the normal range - and could take years - but that doesn't mean that you have enough B12 in your cells - in fact you probably don't. There are test that could confirm that - MMA and homocysteine - but to be honest doing those tests isn't necessary and what you needed is to be being treated properly in accordance with guidelines.

You could try referring your GP to the guidelines - they can access them through the BNF - and you could also try getting your GP to look at the area of the PAS website aimed specifically at helping medical professionals to improve the diagnosis and treatment of PA


Irismay profile image
Irismay in reply to Gambit62

Wow - thank you - I didn't realise there was so much to it. I will try & talk to my GP about this & ask if I could reinstate the injections to see if it makes a difference but I don't hold out much hope! I will gather the evidence that you suggested to take with me. Thank you again for your very helpful reply .

I work in NHS Fife and many people are being given oral VitB12 but occasionally some are still getting injections. I have been so disappointed in the knowledge base of Dr's and even my friend who is a nurse practitioner didn't have a clue. I think when things ease we need to do a mass petition and write to the health minister and also to NHS Boards. I would do it now, but I expect all complaints concerns will be pushed aside due to higher priorities, so we are all just getting by as best we can. Wishing everyone well xx

I’m sorry to hear about your plight . I do hope that you manage to convince your GP to resume your B12 injections , because you are already feeling the effects of B12 deficiency with the exhaustion,brain fog etc.We know how difficult that is . I had to resort to self-injection because I need an injection once a week .So don’t despair if you don’t manage to convince your GP . There is a way out . I know that the idea might appal you , but believe me , you can overcome that — I managed it somehow , and now it’s just routine . Also S.I. Is really cheap . It need cost not much more than £1.00 for an injection — ampoule , needles, syringes and swabs , if you buy in bulk ( 100 of everything )

I want to wish you all the best with your GP.

Irismay profile image
Irismay in reply to wedgewood

Thank you so much Wedgwood , I never realised there was so much help out there. I feel I can now help myself thanks to the great advice. All the best for 2019 & best wishes.

\\o// I had my first injection 3- months ago ! I am told by GP similar diagnosis and the next one due in the new year - Shall report after the blood test - T/Q

Good luck with your injections, I would be very interested in your outcome. All the best.


I am not medically trained.

My experiences suggest that some UK GPs lack understanding of B12 deficiency. I'd suggest doing some B12 homework in case GP has not done theirs....

Some B12 info that may be helpful.

UK B12 documents

BSH Cobalamin and Folate Guidelines

Flowchart from BSH Cobalamin and Folate Guidelines

BMJ B12 article



There is a useful summary of mainly UK B12 documents in third pinned post on this forum.

Unhappy with Treatment (UK info)?

Letters to GPs about B12 deficiency

Lots of useful b12 info in above link with examples of possible letters.

I think writing letters to GPs is likely to be more effective than other methods of passing info. My understanding is that in UK, letters to GPs are filed with a patient's medical notes so are harder to ignore....

CAB NHS Complaints

HDA patient care trust

UK charity that offers free second opinions on medical diagnoses and medical treatment.

B12 books I found useful

"What You Need to Know About Pernicious Anaemia and B12 Deficiency" by Martyn Hooper

Martyn Hooper is the chair of PAS (Pernicious Anaemia Society). Book is up to date with most UK B12 guidelines. I gave a copy of this book to my GPs.

"Living with Pernicious Anaemia and Vitamin B12 Deficiency" by Martyn Hooper

Has several case studies.

"Could it Be B12?: An Epidemic of Misdiagnoses" by Sally Pacholok and JJ. Stuart (USA authors)

Very comprehensive with lots of case studies. There is also a paediatric version of this book "Could It Be B12? Paediatric Edition: What Every Parent Needs to Know".

Other help

1) Blog post about what to do if b12 injections stopped.

2) Have you considered joining PAS (Pernicious Anaemia Society)?

Some PAS members do not have a confirmed diagnosis of PA as getting a diagnosis can be difficult.

Flowchart above from BSH guidelines, outlines when PA and Antibody Negative PA can be diagnosed in UK. Has your GP followed process outlined in flowchart?

PAS (Pernicious Anaemia Society)

Based in Wales, UK.


There is a helpline number that PAS members can ring.

PAS support groups in UK


PAS support groups can be useful sources of info about helpful GPs etc.

UK B12 Blogs

Martyn Hooper's blog about PA

There are stories on here about how PAS has supported people struggling to get PA diagnosis/adequate treatment.

B12 Deficiency Info blog

"cause was never given"

Risk Factors for PA and B12 Deficiency


Have you ever checked your medical records to see if you had a test for PA? in UK, this is an Intrinsic Factor Antibody test (IFA). IFA test is not always reliable and it is still possible to have PA even if IFA result is negative.

Does your GP know it is possible to have Antibody Negative PA? See BSH Cobalamin guidelines link for more info.

Tested for Coeliac disease?

NICE guidelines suggest anyone with unexplained B12, folate or iron deficiencies should be tested for Coeliac disease. Were you tested?

NICE guidelines Coeliac Disease (2015 version)

Coeliac Blood Tests

Tested for H Pylori infection?

Exposure to Nitrous Oxide?

Nitrous Oxide

"brain fog, dizziness"

These would usually be considered neurological symptoms. Do you have other neuro symptoms eg tingling, pins and needles, tinnitus, tremors, memory problems, numbness, balance problems etc....

B12 Deficiency Symptoms


Neurological Consequences of B12 Deficiency

PAS news item


PAS article about SACD, sub acute combined degeneration of the spinal cord, access to PAS members only.

pernicious-anaemia-society.... See Page 2 of articles.

Blog post from Martyn Hooper's blog, mentions SACD

Link about writing letters to GP if under treated for B12 deficiency with neuro symptoms.

Best piece of advice I ever got was to always get copies of my blood test results.

Link about "What to do next" if b12 deficiency suspected

Blood tests


Full Blood Count and Blood Film

Folate Deficiency

Iron Studies

More B12 info in pinned posts on this forum.

Good luck. I hope you get the treatment you need.

If you put "injections stopped" in search box on this forum, you may find other forum members who have had similar experiences.

Irismay profile image
Irismay in reply to Sleepybunny

Hi - my grateful thanks for taking time out to give such a detailed reply. I am new to the forum & am slowly finding my way round it. I have never been told I have PA but I did have a coeliac & helibactor test & they were both negative. I do have terrible memory problems, tinnitus, a burning in my stomach & esophagus (not sure if that's relevant), fatigue, occasional pins & needles in my legs & rib & pain in my back which can be agonising, again not sure if that's relevant either. I am going to work through all your links & try & piece together a picture for my Dr but will probably be met with a degree of resistance based on experience when my mum was very Ill. Many thanks again I am becoming better informed thanks to you helpful people. I was never informed or even realised how important b12 is for bodily function. Good wishes.

Hi again,

"never been told I have PA but I did have a coeliac & helibactor test & they were both negative"

I suggest it's worth checking your medical records/test results to see whether you had BOTH tests listed below for Coeliac disease.

NICE guidelines for Coeliac disease recommend two first line tests

1) tTG IgA

2) Total IgA

UK GPs don't always do the second test, Total IgA.

Total IgA test checks which patients have IgA deficiency. People with IgA deficiency will have a negative result on tTG IgA test even if they have Coeliac disease so they will need alternative tests for Coeliac disease.

If GP only did the tTG IgA test , I don't see how GP can be sure you do not have Coeliac disease. NICE guidelines also indicate that if Coeliac type symptoms continue after negative results in Coeliac blood tests, referral to gastro-enterologist is in order.

Have you ever been referred to a gastro-enterologist?

As you describe neuro type symptoms, have you been referred to a neurologist?

See NICE CKS link in my post above.

Irismay profile image
Irismay in reply to Sleepybunny

Hi - thank you for your detailed reply. I think one of the first things I will do in the new year is request my blood test results. I had a gastroscopy in November & it was ok apart from a dose of esophagitis. I also gave up gluten & dairy a year ago which has greatly improved my ibs. Interestingly, my mum had hyperthyroidism & my daughter has hypothyroidism which I believe can be linked to pa but the thyroid issue seems to have skipped a generation with myself. I have had strange symptoms appear now & again sometimes pointing to an autoimmune problem. I get severe pain & inflammation in joints & bones so was referred to a rheumy & had a couple of mris which showed random bone marrow edema. I did have blood tests at that time so guess they would have checked iga but I'm not sure so will have to look into it. I remember the Dr saying I had a mildly reactive ANA? Forgive my ignorance but I'm sure that was what she said! I also had unilateral sensorineural hearing loss around the same time whiich was tteated with large dose of steroids & recovered some of my hearing but have been left with tinnitus. I really need to look into these symptoms to see if they can be linked to pa or some sort of autoimmune problem. Sorry to drone on but just realised that writing it all down can be quite enlightening! Once again thank you for your great help.


"Dr saying I had a mildly reactive ANA?"

Link about ANA blood test.

Have you been checked for RA (Rheumatoid Arthritis) and Lupus and related conditions such as APS/Hughes Syndrome?

Lupus link


"did have blood tests at that time so guess they would have checked iga "

Probably worth checking your medical records/test results and getting copies. Some UK GP surgeries have online access to a summary of results/records. Details will be on GP surgery website.

"mum had hyperthyroidism & my daughter has hypothyroidism"

Might be worth putting any thyroid results on Thyroid UK forum on HU.

In UK, GPs often only test TSH which won't give a full picture of thyroid function. Is GP aware that there are thyroid problems in your family?

I have read that there can be a link between bone marrow damage and B12 deficiency. I think this can be linked to macrocytosis (enlarged red blood cells). Macrocytosis can be associated with b12 deficiency ( and also with folate deficiency).

Might be worth checking Full Blood Count results to see if there are any indicators of macrocytosis. See link about Full Blood Count in my other post for more info.

Irismay profile image
Irismay in reply to Sleepybunny

Very very useful thank you. I have symptoms of a number of different things but they all point to something autoimmune. It will take some time to paint a picture. I did call into my surgery today to try & get some blood test results but was told to put my request in writing as it will take some time to get them printed off & they were exceptionally busy. Thank you again for your time , I very much appreciate it & I will continue the research. Hopefully I can update you & the forum at a later date & it will help others. All the very best to you for 2019.

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