[Clinical value of a sensitive TSH-RIA].

Based on a sensitive TSH-RIA (measuring-range 0.2-25 mU/l, 50%-intercept 2 mU/l, coefficients of between-assay-variation 5-10%) and on nearly 1200 cases, it is demonstrated that clinical results can be received by determination of basal serum-TSH alone. Values above 0.5 mU TSH/l indicate positive TRH-tests in a good correlation between increasing basal concentrations and pituitary TSH-reserve. TSH-levels below 0.3 mU/l proceed with negative TRH-tests. In selected healthy subjects, we found all TSH-values between 0.7 and nearly 5 mU/l (means = 1.99). In euthyroid goiters, TSH-levels are normally in the same range, but in nodular goiters, subnormal values were found accumulated. TSH-levels below 0.3 mU/l are helpful to discover non-suppressibility. Hormone-treatment of goiters is successful above all in case of high-normal pretherapeutic TSH-values. "Fine-tuning" of hormone-dosage (goiter-treatment, postoperative prophylaxis, suppression-therapy in thyroid carcinoma) as well as monitoring of thyrotoxicosis-treatment is recommended to be performed by means of basal TSH-determination. In pituitary disorders, thyroid hormone-treatment seems to be necessary only at TSH-levels below 0.5 mU/l. Combination of basal TSH and total T-3 is economical and describes nearly all functional situations in diagnosis and treatment of thyroid diseases.