Most of the free hormone immunoassays in current use employ a specific, high affinity hormone antibody to sequester a small amount of total hormone from the specimen. The unoccupied antibody ...

Eun Lee, MD If your healthcare provider has ordered a T4 test, you may wonder what it is. Thyroxine is another name for T4, which is one of the two main types of thyroid hormone the thyroid gland ...

To confirm hypothyroidism, a doctor will typically perform a follow-up test that measures your levels of T4, the main form of thyroid hormone circulating in the blood. A high TSH level and a low ...