Log in
Thyroid UK
93,533 members107,581 posts

Advice for pre blood test

Sorry if I am duplicating things here but not sure how old threads are picked up so thought it best to start again in case my message got lost somewhere on a historical post. 

I have a blood test booked next week and have been advised to take my HRT after blood test so thyroid levels are at their worst for blood test. My blood test is first thing in the morning and I take my HRT just before bed. Should I reduce the time of HRT by a couple of hours each day so that the day before the test I can take it around lunch time instead of bedtime?

Any other advice apart from fasting before blood test?

Is it a good idea to take/avoid foods or exercise or anything like that pre blood test?

3 Replies


If you're having a thyroid function blood test you can take your HRT as normal, it won't affect the thyroid test.  It's Levothyroxine, T3 and NDT which should be taken after the thyroid test.

Arrange the thyroid blood test early in the morning and fast (water only) because TSH is highest early and drops after eating and drinking.


I am not a medical professional and this information is not intended to be a substitute for medical guidance from your own doctor. Please check with your personal physician before applying any of these suggestions.

1 like

I think that sounds sensible although i am certainly no expert - i've done that with some meds sometimes to change the time of day for a long haul flight etc

do have gluten.  if you are gluten free it will not show up on a test.a

i think anything else and they would say :)


Thanks Clutter and Cloud Dog 


You may also like...