A new combined thyroid hormone index based on thyroxine, triiodothyronine and resin uptake.

A new thyroid hormone index, based on measurements of thyroxine (T4), triiodothyronine (T3) and resin uptake (RT3U), is proposed. In contrast to previous thyroid hormone indices, it incorporates both T3 and T4 measurements. This combined thyroid hormone index appears to have superior predictive value in terms of clinical correlation with thyroid disease.