Measures free thyroxine (T4) for active hormone availability, not bound to proteins
Direct thyroid output provides clear insight into hormone production
Accurate metabolism check helps confirm hyperthyroidism or hypothyroidism
Reliable results for women on birth control or pregnant, as these can skew other thyroid tests
Fast turnaround with results typically available within 24 to 48 hours
Summarized by Shop
The T4 Free test measures the amount of "free" thyroxine in your blood. Unlike Total T4, which includes hormone bound to proteins, Free T4 is the active form that is immediately available for your body's tissues to use. This makes it a more accurate reflection of how your thyroid is functioning, especially if you have an abnormal TSH resu
Test Method
Lab analysis
Sample Type
Blood
Kit Components
Sterile lancets, test tube, alcohol prep pads
Turnaround Time
24 to 48 hours
Preparation
No fasting required
Result Delivery
Secure private portal, not shared with insurance providers
