In this communication we intend to describe our experiences with the use of the level of the serum precipitable iodine (SPI) as a laboratory aid in appraising whether a patient with an adenomatous goiter is euthyroid or hyperthyroid. No cases of Graves' disease (exophthalmic goiter) are included. The distinction between the adenomatous goiter and the hyperplastic goiter of Graves' disease appears to be a valid distinction, clinically, pathologically, and possibly etiologically.* Therefore, since we do not consider "hyperthyroidism" to be a single entity, it seems appropriate that this diagnostic technique (the SPI) be evaluated in a single category; namely, the adenomatous goiter.
Many diagnostic difficulties arise in the evaluation of the total functional state of the adenomatous goiter, particularly if the goiter has been present for many years, if other diseases complicate the clinical picture, and if the signs and symptoms of hyperthyroidism are not definite. We frankly confess that