Fluorometric Determination of Tryptophan in Normal and Carcinoid Blood and Urine. Errors in Urine Analysis

Abstract

Lehmann, J. Fluorometric Determination of Tryptophan in Normal and Carcinoid Blood and Urine. Errors in Urine Analysis. Scand. J. clin. Lab. Invest. 22, 72-78, 1968. The fluorometric determination of tryptophan (Try) in blood and urine according to the method of Hess & Udenfriend as modified by Denkcla & Dewey has been reinvestigated. The method was found reliable for blood analysis and normal values were presented. Severe errors were revealed when applying the method to urine, which resulted in low values and poor recoveries, especially from carcinoid urines. The errors could be overcome by dilution of the urines 1:6, which is proposed as a routine method. The low values and recoveries from carcinoid urines could be traced to the secretion of a specific disturbing substance.