Time of blood test

[Geegee777]

Hi, ive booked a blood draw but only time is 10.45am. Its for my nhs endo. My question is does the time its taken make a difference?

[SeasideSusie Remembering]

The time of your test means that your TSH will be lower than it would be if tested at 9am. If you eat before the blood draw this may affect TSH so water only is suggested.

Don't forget that last dose of Levo should be 24 hours before the test to give the most accurate reflection of normal circulating hormone, this avoids any false high result by taking it too close to blood draw or false low by leaving longer than 24 hours.

Also, no biotin, B Complex or any supplement containing Biotin should be left off for 3-7 days before the test as it can give false results.

[Lalatoot]

Geegee I think SeasideSusie meant to say that your TSH will be LOWER than if the bloods were drawn at 9am. Some folks need to get the highest TSH possible to keep their doctor from reducing their dose based on TSH alone which is why early blood tests are recommended on here.

[Geegee777 in reply to Lalatoot]

Hi, my tsh is very low, which is the reason for this test, im looking at increasing levo, but working with my endo az she has agreed to prescribe t3 on nhs

[SeasideSusie Remembering in reply to Lalatoot]

Yes, I did Lalatoot, brain still running on half empty I'll amend my post to avoid confusion. Thanks for pointing it out.

[SmallBlueThing]

Background reading for you:

thyroidpatients.ca/2020/07/...