Pernicious Anaemia Society
14,604 members10,407 posts

Advice needed on b12 injections please :)

Hi everyone,

I was diagnosed with b12 deficiency in February this year (level was 121) and negative IF antibodies. I had 2 weeks of b12 injections and told I'd need an injection every 3 months (last injection was early June), I had some bloods done yesterday (for something else) and asked if they would check my b12 again as have never had it rechecked since having the injections. It is now over 1000 😳 My question is shall I stop going for my 3 monthly jabs as it is so high as I clearly don't need them at the moment? Next one due August.

Thanks for advice x

7 Replies

Personally I would continue with the scheduled injections and let your doctor decide when your B12 is next tested as he/she is the one treating your deficiency. Among the recent test was your Folate level checked?


Hi, yes folate was tested also, it was 4 which was borderline so been on folic acid for 3 months and it's now 20 x


You'll see from the latest BMJ research document below that there is no gold standard test and PA/B12 deficiency is complex to diagnose. You don't say whether any symptoms have improved but, as your B12 was very low, it would not be surprising if they were neurological and these should be treated in accordance with BNF guidelines 'every other day until no further improvement', to prevent permanent damage.

Re blood testing - see bottom of page 4 under 'How is Response to Treatment Assessed' :

"Homocysteine or methylmalonic acid should normalise during the first week of treatment. Failure to do so suggests an incorrect diagnosis, unless renal failure or other causes of increases in the metabolites coexist. Cobalamin and holotranscobalamin levels are not helpful because they increase with vitamin B12 influx regardless of the effectiveness of treatment and further testing is not usually required. They can be tested 1-2 months after starting treatment or if there is no response to treatment.

Neurological recovery may take some time; improvement begins within one week and complete resolution usually occurs between six weeks and three months. Progression should prompt reassessment of the diagnosis. Patients with delayed improvement should be referred for rehabilitation, including physiotherapy. Residual disability is seen in up to 6% of patients. Damage is likely to be irreversible if diagnosis and treatment are delayed by six months.3 24"


I had awful symptoms to start, pins and needles in hands, heavy feet, un co ordinated, weakness, lethargy, headaches, dizzy....I feel loads better now x


It must be really reassuring that you feel so much better Yvonne 🤗 Personally, I would continue to have injections three monthly - PA is for life and many people here have difficulty in getting diagnosis and early treatment, or their injections are then stopped because many GPs wrongly diagnose by blood test only.

Autoimmune disease runs through our family and, unfortunately, we've had to do all our own reading and research. When symptoms similar to yours began after two viruses this year, I began self injecting every other day and will continue to do so. The symptoms have improved immensely but I find they do return with any increased exercise, stress, or infection.

The Dutch research on outcomes and results in the pinned posts here is very interesting and stresses early and adequate treatment on outcomes after a year.

1 like

people vary a lot when it comes to B12. This, along with the fact that serum B12 only tells you how much B12 is in your blood and not what is going on in the cells where it is used, make serum B12 a very difficult test to interpret - and certainly not one that can be used as an indicator on its own.

Being on injections introduces some other factors that mean that the serum B12 normal range really doesn't apply anymore and the test is only useful if it comes back low. Surveys of patients with B12 absorption problems tend to imply that on average people that are being treated need levels north of 1000 - mine need to be completely off the top of the range if I am going to feel okay and be able to function.

so, no you shouldn't go by what the test tells you - you should go by what your symptoms tell you.


They say that once you are on injections there is no point in repeat testing the B12 levels in your blood. Also, only a percentage of what is in your blood, will actually reach your cells. If you feel well on three monthly injections, then stick with it. I am currently getting my injections every six weeks, and that level suits me. Glad you are feeling better.


You may also like...