Factors Affecting Colorimetric Urinary 17-Ketosteroid Determinations¹

THERE are a number of procedures for estimating the 17-ketosteroids in urine extracts by the use of m-dinitrobenzene in alkaline alcoholic solution. These various methods do not give similar results with the same urine extract (Friedgood and Berman, 1941; Strickler, et at. 1941). In this laboratory normal values for 17-ketosteroid excretion obtained with a photoelectric modification of the method of Oesting (1937) have been higher than those reported with some other procedures. The present study was undertaken to establish the usual magnitude of such discrepancies and the basis for these differences.2 The following methods, which represent those most commonly used for the assay of 17-ketosteroids, were selected for study. All utilize the photoelectric colorimeter. A. The Callow (1938) procedure as adapted by Langstroth and Talbot (1939a) and Talbot, et al. (1940a). B. The procedure of Holtorff and Koch (1940). C.