Supplements before bloods

[Spangle15]

Hi

How long before a blood test should I stop taking vitamin D, B12 and folate? Should I stop magnesium too (it’s not being tested).

Thanks

[SeasideSusie Remembering]

Spangle15

You don't stop any of them if it's just thyroid tests you're doing.

For any blood test you stop Biotin or B Complex (it contains Biotin) because this gives false results if Biotin is used in the testing procedure (most labs do).

If you're testing Vit D you can take Vit D supplement up to the day before, on the day of the test take after the blood draw. Same with B12 and folate supplements. However, if taking B12 you should really be taking a B Complex to balance all the B vitamins, not just folate.

If you want a baseline B12 to see how much you are holding on to then you'd leave it off for 4-5 months, otherwise the result reflects the dose you're taking.

[Spangle15 in reply to SeasideSusie]

Thanks Susie. How long in advance should you stop the biotin? I’m having vits/thyroid/ferritin tested after taking vits/iron to try and increase after my last bloods.

[SlowDragon Administrator in reply to Spangle15]

Ideally 5-7 days

Might get away with 3 days if you had to

[Spangle15 in reply to SlowDragon]

Thank you.

[SeasideSusie Remembering in reply to Spangle15]

When testing ferritin/iron, leave iron tablets off for 7 days.

[Spangle15 in reply to SeasideSusie]

Thank you.