T3

About This Test
T3 (triiodothyronine) is one of the main thyroid hormones that sets your body’s “metabolic speed.” It influences heart rate, energy, weight, and temperature control. Levels can be high in overactive thyroid (hyperthyroidism) and low in underactive thyroid (hypothyroidism). Doctors usually read T3 together with TSH and T4 for a complete picture. This test is commonly included in targeted check-ups to support early detection and better monitoring.

Patient Preparation
No fasting needed

Best Time to Test
Morning preferred, but can also be done anytime

Tests Included
T3

Why is it done
Evaluation of symptoms such as palpitations, heat/cold intolerance, weight change, anxiety, or fatigue; confirming suspected hyperthyroidism (T3 may rise earliest); monitoring treatment of thyroid disorders; clarifying borderline or discordant TSH/T4 results.