t3 tests

[esssssssssss]

Hello,

I have recently added T3 on top of taking T4, when should I do my first blood test, am I supposed to wait 6 weeks until it's fully saturated as I was doing that previously with T4 or can I do it quicker. Just wanted to check if my TSH went down as it was high on my last blood test.

[Jaydee1507 Administrator]

You need to wait 6-8 weeks to allow a new dose to settle in your system, in fact longer is probably better.

Do remember the timing of last dose of Levo & T3 before the blood draw which is really important as taking them too soon will show the immediate peak of each hormone as opposed to the stable blood level. Taking them too far away from the blood draw will show a false low. You need to know the stable level so:

Last Levo 24 hours before blood test. Fasting that day and no biotin containing supplements for 4 days before.

Last T3 8-12 hours before blood draw. If you take T3 as one dose then split it just for the day prior to the test.

[esssssssssss in reply to Jaydee1507]

Hi, could you elaborate on how does biotin affect the thyroid/test results as I never stopped taking it 3-5 days before the test

[Jaydee1507 Administrator in reply to esssssssssss]

Biotin is used in the lab blood test process so it can interfere with the test results and give false numbers.

thyroid.org/patient-thyroid...

[SlowDragon Administrator]

important to also test vitamin D, folate, ferritin and B12 at least once a year

Remember to stop taking any supplements that contain biotin 3-5 days before any test

[esssssssssss in reply to SlowDragon]

Hi, could you elaborate on how does biotin affect the thyroid/test results as I never stopped taking it 3-5 days before the test

[SlowDragon Administrator in reply to esssssssssss]

Are you taking a separate biotin supplement or in vitamin B complex

IMPORTANT......If you are taking vitamin B complex, or a separate biotin supplement, remember to stop these 5- 7 days before ALL BLOOD TESTS , as biotin can falsely affect test results

endo.confex.com/endo/2016en...

endocrinenews.endocrine.org...

In week before blood test, when you stop vitamin B complex, you might want to consider taking a separate folate supplement (eg Jarrow methyl folate 400mcg) and continue separate B12

Post discussing how biotin can affect test results

healthunlocked.com/thyroidu...