Stopping B vits before test

[Molly161018]

Just checking, I'm now taking separate B12 drops as well as a B complex - I'm ok to keep taking these drops up until the day before a blood test aren't I? Am I right in thinking it's just supplements containing biotin (ie the B complex in my case) you should stop a week before?

[Jaydee1507 Administrator]

You are correct. Just stop the B complex 4-7 days before and its fine to continue the B12 drops right up until the day before the test.

Recommended blood test protocol: Test at 9am (or as close as possible), fasting, last levo dose 24hrs before the blood draw, last T3 dose 8-12 hours before blood draw & no biotin containing supplements for 3-7 days (Biotin can interfere with thyroid blood results as it is used in the testing process).

Testing like this gives consistency in your results and will show stable blood levels of hormone and highest TSH which varies throughout the day. Taking Levo/T3 just prior to blood draw can show a falsely elevated result and your GP/Endo might change your dose incorrectly as a result.

[Molly161018 in reply to Jaydee1507]

Thanks for confirming jaydee that's v helpful 😊

[SpringerMom in reply to Jaydee1507]

Am I right in thinking that if the blood test includes B12 and folate that this should also be stopped too before testing? It confuses me too.

[Lilian15]

I was told by a haematologist that I must stop all B12 supplements for 3 months before he could do blood test for PA. It is thyroxine that you stop 24 hours before testing.

[Molly161018 in reply to Lilian15]

Yes this is just a thyroid and vitamins test...I was told the same by my GP but I don't believe it was long enough for my b12 to get back to I supplemented anyway...