When to take the last dose of T3 before a blood test?


Aug 15, 2013
If I will have a thyroid blood tests done, let's say on Monday morning, when can I take my last dose of T3 before the blood test?

Currently I'm taking a combination of T4 and T3 at least 6 times a day, the last one around 9-10pm.

Thanks for the help.


Aug 9, 2012
I guess it depends on the purpose for the test.

If you want to check your current TSH, T3, T4 etc, then keep taking it.
If you want to show a doctor that you have a high TSH, then stop a day or two before.
If you want to see how your thyroid does without supplemental meds, then stop about a week or two before the test.
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