THE BINDING OF 131I-TRIIODOTHYRONINE BY SERUM PROTEINS AS AN IN VITRO TEST OF THYROID FUNCTION

Abstract

ABSTRACT The efficiency of Sephadex column chromatography for the separation of free iodide, free T3, and protein bound T3 has been demonstrated. Protein bound T3 and free iodide appear as two well defined peaks of activity in the eluate, while free T3 remains bound to the Sephadex column. This methods makes the direct study of the binding of T3 to serum proteins possible and allows of correction for the free radioactive iodide present as a contaminant. The value of this method in 147 selected patients was demonstrated by the high degree of accuracy in the diagnosis of thyroid function. The clinical diagnosis was confirmed by this method in 141 patients (95.9%) and the test failed in 6 cases (4.1%). The use of this method as a clinical screening test of thyroid function is suggested as it is sufficiently reliable, simple to perform and does not expose the patient to radiation hazards.