What is the Role of Free T4 and Free T3 in Thyroid Function?
Free T4 and free T3 are the active forms of thyroid hormones circulating in the bloodstream. Free T4 is converted into the more potent free T3 in peripheral tissues. Measuring these hormones provides a clear picture of thyroid function. Histologically, changes in follicular cell height and colloid content may correlate with variations in T4 and T3 levels.