Free T4 test
The main hormone your thyroid makes.
€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: tiroxina libera, T4 libera
Free T4 test: what it is for
FT4 is free thyroxine: the part of your thyroid’s main hormone that circulates freely in your blood, ready to enter your cells. It is almost always read together with TSH, the hormone your pituitary uses to tell your thyroid to work harder or less.
When it is done
Doctors mostly order it when TSH is outside the limits, to see how much your thyroid is really working. They also order it if you have symptoms of a slow or fast thyroid, if you take thyroid hormone, or if there are pituitary problems.
To check the thyroid in people who feel well, TSH is usually enough: it moves first and says a lot on its own. FT4 comes next, to understand what is going on.
How the free T4 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 T4 test.
Do I need to fast for the free T4 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. If you take levothyroxine, ask your doctor whether to take it after the draw.
How much does the free T4 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 T4 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.
