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Thyroid UK
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Just trying to get my head around vitamin B12 and related issues!

Can anyone explain how I can have a low serum B12 level 284 ng/L reference range (223 - 1132) and yet my serum folate was 14.8 ug/L (4.6 - 18.7)?

I thought that being low in B12 was linked with folate as they work in synergy. A simple explanation will suffice please!

I was supplementing for 3 months with sublingual spray from well known shop but didn't really feel any benefit (1200 ug) daily yet my GP is not convinced that the random pin prick / stabbing all over including my eye balls is related to this at all.

My rheumatologist asked last week why my GP has not started me on injections (in light to the fact I am hypothyroid and coeliac and under investigation for UCTD)!! Also,there are autoimmune conditions galore in my family and my grandma had pernicious anaemia.

I decided to stop taking the sublingual on 30th January so that I could order an active B12 test. This is now 6 weeks and so do you think this a good plan?

Thanks in advance

5 Replies

PS: My ferritin was 250 two years ago and last year it came down to 180. Sorry, no reference ranges.


Can't you ask the Rheumy to write to the GP telling him to prescribe B12 injections? If he thinks you should be on them, then he should be instructing the GP to prescribe in my opinion. The best and cheapest test for deficiency is actually a trial of treatment.

Having blood tests after taking B12 supplements is a really difficult one to call, it can stay in your bloodstream for months. I have heard anecdotal mention of people needing 4 months clear of them to get an accurate result, but everyone is different so it's really hard to say.

One option might be to ask the doc or Rheumy to do the antibody tests first; anti-intrinsic factor and anti-parietal cells. Or if the Rheumy is particularly amenable he might do MMA (methylmalonic acid) or homocysteine tests for you (my Endo arranged the MMA test for me).

B12 and folate do work together, but people don't always have low folate levels when they have low B12. In fact sometimes they are high because the folate starts to build up unmetabolised without any B12 to work with. In this situation you would actually still be folate deficient, and perhaps have low red cell folate or high homocysteine.

I'll leave you with a B12 link anyway: b12deficiency.info

H x



Last year I supplemented with B12 sublingual spray for 5 months and stopped for 2 months to have the active B12 test and the level came back at 107 range 25 - 108.

I had the test done again last month (4 months after stopping supplements) and level was 69 range 25.1 - 165

(different company) So even though the ranges are different you can see that the supplement must have still been in my system after 2 months but has now decreased significantly.

I have my endo. appt. next week so I am hoping he will do the other tests hampster1 suggested.

Like you I now get an awful pin pricking sensation along with itching pins and needles and tingling.


The rheumatologist didn't seem that interested and in fact, said he knew little about vitamin B12 deficiency as it wasn't his sphere and suggested that my GP followed this up. Really? I was quite shocked to say the least. Also, for my pain, he said he didn't know what else to give me when I said OTC meds don't work when I am in a flare. I was flabbergasted indeed.

This was reiterated further when I told him my optician wanted to refer me to an eye consultant to check my cornea (I take Plaquenil for my joint pain), he asked me to get my GP to do the referral because his funding wouldn't allow this! Whatever happened to holistic care, treating the whole person?

All in all, I am sure you can imagine why I have begun to explore the possibility of seeing another rheumatologist as I posted on Lupus UK last week.



Read this today. Raises more questions than it answers, I think.



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