Radioimmunological determination of triiodo-thyronine (T3) and thyroidastimulating hormone (TSH) in routine diagnosis

The radioimmunological determination of triiodothyronine and thyroid-stimulating hormone (TSH) provides two new methods for functional diagnoses of the thyroid. Changes and disturbances of the control mechanism had been difficult to detect with conventional methods. The measurement of the basal TSH rate has further therapeutic and diagnostic consequences such as, e.g., the determination of growth stages of strumae or preclinical hypothyreosis on the basis of increased basal TSH values. The results of the TRH test enable a more exact clarification. Substitution therapy should take into account the rate of the remaining basal TSH secretion as well as the clinical picture. The determination of the serum T3 concentration enables the diagnosis of isolated triiodothyronine hyperthyreosis. Continuous control of the thyrostatic therapy by T3 and TSH determination helps to prevent a condition in which hyperthyreosis persists even though all the normal parameters indicate a euthyroid function. The development of a preclinical hypothyreosis can also be detected early. The increased basal TSH secretion after strumectomy is a further proof of the urgent need for consequent prophylaxis of relapses (orig./AK)