Individual test · Labcorp 070104

Reverse T3

This test measures the level of Reverse T3, an inactive form of thyroid hormone that your body creates from T4. It helps show how well your body converts thyroid hormones and is often checked when standard tests appear normal despite symptoms of fatigue or metabolism issues. This measurement helps doctors distinguish between a primary thyroid problem and thyroid changes caused by other serious illnesses or severe physical stress. However, this test cannot diagnose a specific thyroid disease on its own and must be interpreted alongside other thyroid markers like TSH and Free T3.