Laboratory examination of the thyroid. I. In vitro tests

There are many methods for evaluating thyroid disease, but one or two relatively simple tests are adequate in most cases. The more specialized tests or combinations of tests are useful in the few patients who have unusual thyroid disorders or equivocal results in the simpler tests. Basic tests include protein-boung iodine, T4 by displacement, T3 resin uptake, and free T4 index. Valuable tests not yet widely available include T3 and TSH radioimmunoassays. (U.S.)