Can someone explain results

[sbadd]

Can someone explain to me what active b12 means as normal but b12 low

[Gambit62 Administrator]

active B12 measures B12 bound to a particular protein TC11 - which facilitates transfer from blood to cells. Serum B12 measures all the B12 in blood.

Usually the ratio between serum B12 and active B12 is 5:1. Yours appears to be less than 2:1

So, as it says, on the face of it you have enough bio-available B12 in your blood to imply it shouldn't be a problem.

serum B12 is not a particularly accurate test and repeating the test several times on the same sample would give a variation of 20% in the results - but this wouldn't explain why your serum to active ratio is so low.

Not aware of a definitive explanation - possible that there is some (rare) genetic factor going on. If you are feeling highly symptomatic of B12 deficiency - and any other conditions that can cause overlapping symptoms are well controlled so can be ruled out - then it may be worth looking in to whether your cells actually have enough B12 - test for this would be MMA and homocysteine (two products which will build up if not enough B12 is actually getting into your cells).

If you have an earlier serum B12 test that shows a significantly higher B12 level (>20% more) then that would be indicative of a B12 absorption problem as people tend to maintain serum B12 levels at the point that is right for them using stores in the liver, but if you have an absorption problem it also affects the efficeincy with which you can use this store and serum levels in blood fall.

[sbadd in reply to Gambit62]

Thankyou i have had the instrinsic test done which was negative but doct did start me on loading doses which i finished 6 weeks ago, only had tiredness and odd muscle twitch prior to injections but the bad side effects after injections ie head pressure, dizziness, increased numbness and tingling in feet and heavy legs, most symptons have gone apart from odd muscle twitch and heavy legs, slight tingling in feet still present, so just wondering should i have been on injections to start with, i also have underactive thyroid which has been treated for around 4 years now, that was retested and fine atm on my meds?

[Gambit62 Administrator in reply to sbadd]

good that GP put you on loading doses and they have helped.

Symptoms can get a bit worse after you start treatment, and 6 weeks is still quite early days.

Was anything said about maintenance doses?

Worth keeping a diary of symptoms.

[sbadd in reply to Gambit62]

Yes maintenance dose 3 monthly so another 6 weeks away, just mainly the heavy legs thats getting to me

[Gambit62 Administrator in reply to sbadd]

3months doesn't suit everyone and it may well be that it doesn't suit you. Keep a diary of symptoms and see how the numbness and tiredness change at your next maitenance shot - it may be that you really need shots much more frequently than the 3 months - though trying to get that is another story altogether.