This test measures the total amount of T3 produced by the body. T3 or triiodothyronine is the active form of the thyroid hormone. T3 acts as a metabolic throttle for fueling all of the daily cellular functions. Hypothyroidism is a condition where T3 blood levels are low. This causes cellular dysfunction and metabolic breakdown. Symptoms are weight gain, constipation, dry skin and hair loss. Low T3 levels may even lead to the development of chronic diseases such as heart disease and diabetes. Hyperthyroidism is the term for elevated T3 blood levels. Symptoms are anxiety, insomnia, heart palpitations, and bowel discomfort.
Fasting is not required for this test. Take all medications as prescribed.