Radioimmunoassay for Human Thyrotrophin

Abstract

The clinical usefulness of a radioimmunoassay for human thyrotrophin (h-TSH) has been evaluated in 915 subjects with and without thyroid abnormality. The range of values for serum thyrotrophin for 95% of euthyroid subjects was 2.0 to 15.2 µunits of Human Research Standard A per milliliter of serum. The distribution of values with age defined a parabolic relationship, being higher in the early and late decades of life. The discrimination of the assay is greater in the diagnosis of myxedema than any other available thyroid function test, and it offers the most direct and reliable means of differentiating primary and secondary myxedemas. The assay does not adequately differentiate hypopituitarism from normal status. The usefulness of the assay also was examined in a variety of other thyroid and endocrine abnormalities, but levels in general correlated best with conditions involving the hypothyroid state. The radioimmunoassay for human thyrotrophin is a valuable addition to routine tests of thyroid function in man.