Can b12 be high in blood but still be deficient in cells? I was given b12 injections in 2015 by gp but no further testing was done to see if I was deficient or had pa. I did not like the way they did not last and started taking 1000 sublingual daily which have kept all my symptoms away. 2months ago I started getting nerve pain in my ankles going up to my knees and prickly feeling in my feet and gp diagnosed tarsel tunnel syndrome. When the same thing started in my wrists and hands I had a medichecks blood test done. My results were;
B12……..190……..range 25 to 165
Folate…..7.9..range above 2.9 which is halfway on the slider graph.
I have stopped the b12 for now, but am I wrong in thinking too much is better than not enough and is there another blood test to see if it’s getting into the cells?
I do have a gene problem that gives me high homocysteine but the b12 is working on that.
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Auntyp62
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Had doctor appointment via telephone to be told …what do you expect if you are high in b12, what do you want me to do about it? He did give me co-codamol. So I am on my own with whatever is causing this. I only stopped taking this week 2 months after symptoms started. after my blood test results and after I spoke to doctor. Thanks for the reply
are you getting confused with cautions about not supplementing folate before a B12 deficiency is resolved as that can in very rare cases lead to neurological damage
Well , people do get their B vitamins muddled ! Believe it or not ,my own GP did I didn’t dare correct him , which was stupid I suppose . B 12 is certainly not toxic in any way . But some Bs are . But i have read that if you have a very high B12 reading and you aren’t supplementing in any way , it can be a sign of liver trouble .
A word of caution, a high b12 can mask low folate and vice versa : high folate can mask low b12 . Low folate symptoms can mirror low b12 . And I’m certainly in the camp through reading various journals that high b12 is completely harmless other than masking low folate
No such thing as too much B12 - what you don’t need/can’t use gets processed into urine. Too much B6 can cause tingling in feet/hands - check the dosage within any other vitamins you take. MCV can be used as a proxy as to whether the B12 is in the cells. If you’re B12 deficient it will slowly move up. But be aware it’s a slow indicator so if you’re in range it doesn’t mean you’re not deficient- look at the results across the years or decades. It’s about your symptoms not your blood work! Also there is an uncommon hypothyroidism which needs correcting before the B12 can take effect. I doubt this is you, as the supplements were working. I would look at what else you’re taking. Sorry this is sooo looong!
I think you are muddling b6 and b12 up. There has been no research to show b12 at a high level from supplements or injection will cause those effects or anything apart from possibly pink wee. Too much b6 does cause such symptoms and that why you need to be careful when taking a b complex.
If you wish to test for functional B12 deficiency then there are two metabolites - MMA and homocysteine that will be raised if there isn't enough B12 available at the cellular level. The tests general need to be done at a hospital in the UK. They also need to be done in a context that rules out other causes of elevation - kidney function for MMA and B9 deficiency for homocysteine.There are also some haematologist that think that these tests may not tell the whole story.
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B12 deficient but now too high and treatment removed.
Could my Mum be B12 deficient? 
Urine vs blood for B vitamins - anyone understand why one could be high and one low?
B12 deficient but don’t know why
