THE LEVEL of the blood iodine has been widely recognized as a valuable diagnostic aid in differentiating thyroid from nonthyroid disease. Consequently it becomes of importance to determine whether or not blood iodine values ordinarily deviate from the normal in diseases other than of the thyroid gland. Moreover, it is necessary to learn the degree of deviation as well as the nature of the pathologic states in which such variations may occur. Too, any abnormality in the level of the blood iodine in nonthyroid disease might suggest that the thyroid gland was either primarily or secondarily involved.
In contrast to those involving the thyroid gland, nonthyroid diseases in general affect the basal metabolic rate less characteristically1 and even more seldom cause an increase or decrease of the blood iodine. This was revealed by an investigation of representative patients with one hundred and fifteen different nonthyroid diseases (tables 1, 3