The Reverse T3 (rT3) test measures levels of reverse triiodothyronine, an inactive form of the thyroid hormone T3. Reverse T3 is produced when the body converts thyroxine (T4) into an inactive form rather than active T3, often as part of a stress or illness response.
This test is sometimes used as part of a comprehensive thyroid evaluation to help assess thyroid hormone conversion and metabolic regulation. Elevated rT3 levels may be seen during illness, stress, inflammation, or calorie restriction. Results are interpreted alongside TSH, free T4, and free T3 for a more complete assessment of thyroid function.
Reverse T3
The Reverse T3 (rT3) test measures levels of reverse triiodothyronine, an inactive form of the thyroid hormone T3. Reverse T3 is produced when the body converts thyroxine (T4) into an inactive form rather than active T3, often as part of a stress or illness response.
This test is sometimes used as part of a comprehensive thyroid evaluation to help assess thyroid hormone conversion and metabolic regulation. Elevated rT3 levels may be seen during illness, stress, inflammation, or calorie restriction. Results are interpreted alongside TSH, free T4, and free T3 for a more complete assessment of thyroid function.
