Diagnostic procedures in thyroid disease.

Various diagnostic aids may be used to supplement clinical investigation when either the patient is still only suspected of raised or lowered thyroid function, or when the pathology of his thyroid lump still remains in doubt. We shall consider in this paper, the various tests available for assessing the level of thyroid secretory activity; of these there are three main tests and at least three subsidiary indirect tests each with its own special usefulness and its limitations. Since the advent of radioiodine and also of improved techniques for the micro-chemical estimation of iodine, tests of iodine metabolism have tended to dominate this field, but they have not yet completely supplanted either the older B.M.R. or the various subsidiary tests. Space does not permit consideration of the uses of needle biopsy of the thyroid or of thyroid scanning after radioiodine, procedures which are especially useful for the diagnosis of thyroid nodules and of suspected lymphadenoid goitre. The finding of a raised serum gamma-globulin is also a useful confirmatory sign of a lymphadenoid goitre.