T3/T4 blood test timing

[JBLOVELL]

I take all my thyroid meds at 7.30am every morning; that’s 125mg levothyroxine and 50mcg t3 (I find it suits me better than splitting the dose). What should I do before a blood test? TIA

[Haze1975]

Most people will advise you to. Not take any levothyroxine and T3. 24 hours before your blood test. And then take your tablets after a blood test.

[waveylines]

Im on a ndt so dont take mine for 24hrs before testing. I think for T3 meds like liothyronine its 12hrs.....

[SlowDragon Administrator]

Recommended on here that all thyroid blood tests should ideally be done as early as possible in morning and before eating or drinking anything other than water and last dose levothyroxine 24 hours before test

On day before blood test, split T3 into 3 smaller doses, at roughly equal 8 hour intervals, taking last 1/3rd of daily dose approx 8-12 hours before test

So on 50mcg, taking 20mcg waking, 20mcg early afternoon, 10mcg at 9pm …..assuming testing 9am

Only do private testing early Monday or Tuesday morning

If testing iron levels stop iron supplements a week before testing

If taking any supplements that contain biotin stop these a week before all blood tests as biotin can falsely affect test results

[JBLOVELL in reply to SlowDragon]

Thank you so much. I’m doing private, so why should I do them Monday or Tuesday?

[Gingernut44 in reply to JBLOVELL]

To make sure your blood gets to the Lab and is processed before the weekend

[SeasideSusie Remembering in reply to JBLOVELL]

JBLOVELL

I’m doing private, so why should I do them Monday or Tuesday?

The lab's instructions should say to post the sample the day you do the test to arrive as soon as possible. This is to ensure that the blood is as fresh as possible, minimal deterioration so as to give the most accurate results. Ideally the blood should be at the lab the next day.

They usually include a Tracked24 return envelope but this does not guarantee next day delivery. If you use this envelope then your sample may arrive the next day, may take 2 days or may (rarely) be delayed longer. If you post on a Wednesday or Thursday then there's a chance it wont arrive in time and will be hanging around over the weekend and the blood could spoil. Obviously never post on a Friday because the lab doesn't work over the weekend even if it is delivered.

So to allow for any delay we suggest one of two things - post Monday or Tuesday with the Tracked24 envelope or go into the post office counter, purchase Special Delivery Guaranteed Next Day by 1pm and that service should mean that your sample will arrive next day (if it's delayed then you can claim the cost of the service back by quoting the tracking number on the receipt you will be given).

[mountainice in reply to SlowDragon]

Does it matter if levo is 25 hours before?

[SlowDragon Administrator in reply to mountainice]

no …that’s fine ….close enough to 24 hours

[mountainice in reply to SlowDragon]

Thank you.

[RoboTh]

I did mine Tues morning,posted & received results Wednesday morning!

[RoboTh in reply to RoboTh]

I actually asked the nurse doing my nhs bloods to take some extra, they used a yellow blood bottle and I poured the blood into the private blood bottle. Id never be able to get blood out of my finger