TRI IODOTHYRONINE (T3)

"This test measures T3, the active thyroid hormone that directly influences metabolism, heart rate, and energy production. It is essential when symptoms of an overactive thyroid are present, such as anxiety, weight loss, palpitations, or heat intolerance. T3 testing is often used alongside TSH and T4 when thyroid function results are unclear or inconsistent.

Preparation: No fasting. High-dose biotin supplements may interfere; follow clinic advice."