medication timing and blood tests

[Grbca]

I usually take my levothyroxine medication at 7.30am but tomorrow I have blood tests for the Endocrinologist at 9.15am. Last time I took my medication usual time but I have seen a few posts that suggest I should take my medication after the blood tests. Can you advise? My thyroidectomy was in August 2024 this is all quite new to me.

[tattybogle]

Hi, you should delay taking tomorrows dose until after the blood test .

( it's a good idea to hide the packet from yourself tonight , so you don't take it on autopilot when you wake up )

the reasons/ evidence why it's advisable to take last dose about 24 hrs before test are in the first few replies to this post : healthunlocked.com/thyroidu.... list-of-references

basically ....about an hour after you take levo, the fT4 level goes up quite sharply, stay there for a bit , then falls to a more stable level ... you want to be measuring the average level you have all day ,,, not this short lived 'peak' . So the most consistent way to test is ' about 24hrs from last dose'

if the GP is only testing TSH , this doesn't matter , as it only affects the fT4 level, the TSH result will probably be same whether you took it that morning or not cos TSH takes longer to react ... but since you never know when they might test fT4 , it;s a good habit to get into anyway.

[Grbca in reply to tattybogle]

Thank you.

[Buddy195 Administrator]

Forum advice re timings of blood draw:

a)complete thyroid blood tests early morning (preferably before 9am)

b) drink only water before the blood draw

C) ensure your last dose of Levothyroxine is 24 hours before the test (ie take your daily Levo AFTER the blood draw).

This ensures highest TSH reading, lowest FT4 reading and offers consistent results. (Please note, this is a patient-to-patient tip)

[Grbca in reply to Buddy195]

Thanks very much!

[deb25426]

I always take mine after blood test. And I always do my blood tests as a fasting one(that’s my personal choice but not essential unless specified.

[helvella Administrator]

helvella - Scheduling Blood Draws

Factors to consider when choosing time for blood draws. Includes links to several documents/webpages and previous HealthUnlocked posts.

Last updated 12/08/2024

helvella.blogspot.com/p/hel...