Free T3 test
The active form of thyroid hormone.
€13.66. You pay at the desk, not online.
- Preparation: Fasting: depends on the lab. Biotin: ask your doctor
- Prescription: Not needed
- Results: In the Rosa app, within 10 working days
- Also called: triiodotironina libera, T3 libera
Free T3 test: what it is for
FT3 is free triiodothyronine: the active form of thyroid hormone, the one that actually makes your cells work. Most of it is made from FT4, which your body converts in the tissues. Doctors read it together with TSH and FT4.
When it is done
Doctors mostly order it when they suspect a thyroid that works too hard: if TSH is low, FT3 helps show by how much. Sometimes it is the only hormone that rises, while FT4 stays normal.
For a slow thyroid it matters less: TSH and FT4 count there, and FT3 often stays normal for a long time.
How the free T3 test is done
It is a blood test, done at a Bianalisi lab without a prescription. You can add other tests to the same draw.
Questions about the free T3 test.
Do I need to fast for the free T3 test? It depends on the lab, and it is often done with other tests that need fasting. If you take biotin, the kind in hair, skin and nail supplements, ask your doctor whether to stop it at least two days before the draw, and tell the lab: it can skew the result.
How much does the free T3 test cost? €13.66, from Bianalisi’s private list for Lombardy. You pay at the desk on the day of the draw, not online.
Do I need a prescription for the free T3 test? No. You book it here without a prescription and pay at the Bianalisi desk.
When do results arrive? Within 10 working days, in the Rosa app, with each value next to the lab’s interval. The report a doctor approves is in the Rosa membership.
