Blood test waiting period after taking high strength B12 sub-lingually for a couple of years?

[seamail57]

I started self-medicating a couple of years ago with daily sub-lingual 5000 mcg B12 tablets topped up more recently with a sub-lingual spray. My symptoms (mostly neurological) largely receded but more recently they seem to be returning. When my levels were tested three years ago they were found to be in the “normal” range (224), so GP wouldn’t prescribe injections, hence my decision to self medicate.

My question is, how long would it take after stopping my B12 tablets for my blood levels to return to “normal”, so that an accurate blood test could be taken without any residual methylcobalamin B12 skewing the results ? Are we talking weeks? Months? A subsequent blood test taken 9 months after taking daily high dose methylcobalamin showed a reading of 1259 for example.

If so, I’m worried about suffering the effects of deficiency whilst waiting for my B12 blood levels to stabilise. I have a real problem with balance (amongst other symptoms) and I’m concerned about having a fall. I also suspect (like many of you), it will be another uphill battle trying to convince the GP that I have a deficiency problem especially if my blood levels are still in the “normal” range. The only physical proof I’ve got is vertical ridges on my nails, no lunulas (half moons) on my nails and maybe a demonstration that I can’t balance on one leg for more than a second or two !

[fbirder]

What are you trying to prove?

That you have an absorption problem and, therefore, need injections? If so, then you don't need to wait any time at all, because you won't be absorbing anything from the supplements.

That you are absorbing the supplements and they are all that are keeping your blood levels very high (1259 is waaaay above 'normal')? Then you'll have to wait at least three months, probably closer to six. But why? Your levels are as high as they would be with injections.

That you have a functional deficiency? You are absorbing the B12 from the supplements but it's not doing its job. If you wait six months and the levels go down then it will tell you nothing. You need to have tests for MMA and homocysteine (two chemicals used up in reactions mediated by B12). If the B12 is not getting into the cells then these will both be high.

[seamail57 in reply to fbirder]

I’m a little confused.... if I go to a GP for a blood test with such high B12 levels surely they will say I don’t have a problem? (they did in the past!). How do I persuade the GP to do the MMA and homocysteine tests if they insist I’m not deficient? More recently I’ve come round to thinking this too, in that I’m flooding my body with B12 (as best as I can with what’s available to me) but very little of the B12 is active.

Are these tests conclusive? I thought the BMJ advice etc was to treat the symptoms regardless of test results, when it comes to neurological symptoms ? But again, I can see problems trying to convince a GP of this ☹️

[fbirder in reply to seamail57]

If you go to the GP with very high levels while taking supplements, then have low levels when not taking supplements, they will, quite rightly, say that you do not have a problem absorbing the B12.

This is an article from the BMJ journal Practical Neurology that describes a case of somebody with normal levels of B12 but with subacute combined degeneration of the spinal cord. They recommend MMA and hCys testing. pn.bmj.com/content/9/1/37.s...

You could try sending a printout to the GP along with a covering letter asking for the MMA test to be done. Or you could have the test done privately - medichecks.com/tests/methyl... - and then write to the GP with the result if it is high.

If your symptoms are mainly neurological then you should have seen a neurologist. Did they say that the symptoms were caused by a B12 deficiency?

The BMJ advice isn't to treat symptoms regardless of test results. It is that the test results shouldn't be the final word. The problem is that there are many, many possible causes of many of the symptoms of a B12 deficiency. The doctors need good grounds to suspect a deficiency before they start giving injections.

Besides, in your case the doctors will say that any B12 deficiency has been treated. Your serum levels are up where you'd expect them to be if you were having injections.

[seamail57]

Had symptoms (but not just neurological, also cold extremities, palpitations/ breathlessness, outer third of eyebrows missing, no lunula etc) took B12, symptoms all but disappeared - stopped taking B12, symptoms came back, so there is clearly a problem. Thanks for your input anyway.

[fbirder in reply to seamail57]

So you keep on taking the B12.

[ilyfunnybunny in reply to seamail57]

Hi seamail57,

Those symptoms also sound a lot like classic hypothyroidism. Have you had your thyroid levels checked, and if so, what were they?

(Note: Hypothyroidism frequently results in B12 deficiency, so maybe that's a piece of your puzzle.)

[Greena51]

I was taking oral B12 over a few weeks before getting my PA diagnosis in September of last year. My serum B12 went from 214 pg/mL to >1500 in a month of once daily 1000mg B12 and back down to 404 after stopping treatment for three weeks. I did not see improvement in my symptoms until I started injections.

[seamail57 in reply to Greena51]

Thank you , that sounds very much like my situation. It appears the methylcobalamin tablets I’ve been taking are having less effect recently 🙁

[Greena51 in reply to seamail57]

Have you been tested for intrinsic factor antibodies? It might be easier to convince a doctor to prescribe injections with a PA diagnosis. The test can show a false negative but it may be worth a try.

[seamail57 in reply to Greena51]

Yes I have, result was negative. My father had PA though, which I believe can be hereditary ....

[Greena51]

Another test could show a positive result, but if B12 helps your symptoms then that’s what you need! Others on the forum know more about supplements but I take a daily multivitamin also. I wish you well. 😊

[seamail57 in reply to Greena51]

Thank you 😊

[Boo222]

This is rather lengthy but you may find something of interest. I think since it was written the BMJ now recommend 2-3 months rather than the stonewall 3 recommended previously.

facebook.com/notes/pernicio...

[seamail57 in reply to Boo222]

Thanks, but broken link unfortunately ☹️

[Boo222 in reply to seamail57]

Sorry. Does this work?

1drv.ms/w/s!AuJQp_sQsjsUhO8...

[seamail57 in reply to Boo222]

Yes it does, thank you ! 😃 Interesting about not taking supplements before blood testing as this will skew the results, as this was my original question to this forum!

[fbirder in reply to Boo222]

I can’t access that page because I am banned from that Facebook group for daring to point out evidence for 5000 mcg daily doses of folic acid being dangerous.

However, it is the BNF that carries the recommendations for dosing regimens - bnf.nice.org.uk/drug/hydrox...

[seamail57 in reply to fbirder]

“5000 mcg daily doses of B12 being dangerous” Care to elaborate?

I’ve read the BNF article and under “Cautions” can’t really see anything one would classify as dangerous .....

[fbirder in reply to seamail57]

D’oh! That should read ‘folic acids’.

I’ve edited it. Thanks.

[seamail57 in reply to fbirder]

Thanks for clarifying 😊