The diagnosis of thyroid disorders remains a difficult undertaking. The determinations of protein-bound iodine, radioactive iodine uptake, basal metabolism rate, and the various methods of determining thyroxine (T4) and triiodothyronine (T3) in the serum of the patient, complemented by scanning of the thyroid and by the observation of clinical symptoms, do not always give a clear picture of the thyroid status or are too expensive and too complicated to be performed when only a slight suspicion of thyroid abnormality exists.
Vivian Chan and co-workers1 at St. Bartholomew Hospital in London, in cooperation with the Institute of Nuclear Medicine at the Middlesex Hospital Medical School in London, developed a new, modified procedure for extraction of T4 and T3 by radioimmunoassay from urine. Since triiodothyronine contributes significantly to the metabolic activities of the thyroid gland, and since it has been suggested that part of thyroxine is converted to
Two New Approaches to the Diagnosis of Thyroid Disorders. JAMA. 1972;222(2):208. doi:10.1001/jama.1972.03210020054014