Medichecks - stop b12 for 2 weeks prior to testing

[Needleandthread44]

Hi

I want to order my dad a full thyroid testing panel +antibodies and vitamins. However,he has previously had low b12 so was taking intramuscular injections until 1 month ago and is now taking the spray. I notice it says to stop taking any b12 for 2 whole weeks before testing. I wondered whether this will benecessary as I worry that it could impact him? Will the b12 injections that he had a month ago be skewing results anyway?

any advice would be appreciated

[SeasideSusie Remembering]

Needleandthread44

Taking B12 injections/supplements will always give a high B12 level. There is no point in testing. However, I appreciate that the B12 test is part and parcel of the bundle and you can't opt out, so I suggest he continues with what he is doing regarding B12 supplementation and just know that his B12 result will come back high.

Don't ask for doctor's comments, they're pretty useless anyway but you don't really want them commenting on his high B12 level when you know why it's high.

Presumably because he is taking B12 then he will also be taking a B Complex to balance all the B vitamins, this will contain biotin (B7) so he should stop the B Complex for 3-7 days before the test as taking biotin can give false results when the lab uses biotin in the testing procedure - and Medichecks do.