The I131 thigh neck clearance test in relation to drug administration

Abstract

Abstract500 patients have been examined by the I131 thigh neck clearance test, and the results correlated with clinical data and estimations of basal metabolic rate. The test consists in the oral administration of 30 μc of I131, followed by alternate neck and thigh counts under defined conditions over the following one to two hours. The clearance represents the ratio of the rise in neck counts over a 60 minute period divided by the mean thigh count taken at the same time, and gives normal figures of from 1 to 9.In untreated patients there is good correlation in the B.M.R., but as with other radioactive tests of thyroid function, discrepancies occur after various forms of medical treatment. A. number of goitrogens and blocking agents were tested for their ability to limit the retention of I311 by the thyroid if given at the conclusion of the test. Of these potassium iodide gave the best results but is not recommended for routine use.