Blood test

[JMB78]

I'm having a blood test tomorrow at 3pm for a full TSH panel. Should I take my thyroxine in the morning?

Sorry if it has been asked before

[Lalatoot]

The advice is lats dose of thyroxine 24 hours before test. Many follow this advice but others just take their dose as normal.

The reason 24 hours is suggested is so that your ft4 level is at its lowest. This means consistency for results as you will always be measuring the low point rather than it going up and down as it enters the system.

[cjrsquared]

Suggest you look at SeasideSusie response to the same enquiry from last night. Good explanation. Depending on the reason for the blood test it may be a waste of time to have it in the afternoon.

[SeasideSusie Remembering]

Reply that cjrsquared is referring to in the first one in response to this post:

healthunlocked.com/thyroidu...

[SlowDragon Administrator]

Recommended to always get blood test done as early as possible in morning before eating or drinking anything other than water and last dose levothyroxine 24 hours before test

This gives highest TSH and lowest Ft4

Important if you are hoping to get dose increase in levothyroxine

Important to regularly retest vitamin D, folate, ferritin and B12

If taking any supplements that contain biotin you need to stop these a week before ALL Blood tests as biotin can falsely affect test results

[JMB78]

Thank you for all of the advice. I will be changing the appointment now.