Prep for GP Hypo review blood test

[Lionmess]

My GP has asked me to have a blood test as part of my Hashis review for Levo repeat prescription.

I usually do a Private full test myself each May. I know that for that I need to avoid B12, Biotin to ensure more helpful results but does it matter about avoiding those in advance of the basic TSH test.

I'd hate to give them cause to reduce my dose because of my error.

Many Thanks

[SeasideSusie Remembering]

Lionmess

Biotin, or any supplement containing biotin such as B Complex, hair and nail supplement, should be left off for 3-7 days before any blood test as it can give false results when biotin is used in the testing procedure (which most labs do).

The smaller amounts in a B Complex should be fine with leaving off for 3 days, the higher amounts in a stand alone or hair/nail supplement is best left off for 7 days.