Description
The Free T4 test measures the amount of unbound (active) thyroxine hormone circulating in your blood. T4 is produced by the thyroid gland and plays a critical role in regulating your metabolism, energy levels, heart function, and body temperature.
This test is especially important because it helps:
- Diagnose thyroid disorders such as hypothyroidism (underactive thyroid) or hyperthyroidism (overactive thyroid)
- Monitor ongoing thyroid treatment to ensure proper dosing of medications like levothyroxine
- Determine the root cause of abnormal thyroid hormone levels—whether it’s a thyroid issue or a problem with the pituitary gland
Even if your TSH (Thyroid Stimulating Hormone) levels are normal, abnormal Free T4 levels can still indicate a thyroid imbalance.
Fasting not required.
This simple blood test can provide valuable insight into your overall hormone and metabolic health.
