ELISA inhibition technique for the demonstration of sulphones in body fluids

Sum mary A n enzyme-linked immunosorbent assay ( ELISA) for sulphones in urine is described . This method for monitoring dapsone ( D D S) self­ administration is comp ared with the quantitative d etermination of DDS/ creatinine (D/C) rat io s, currently used . Urine samples collected from 1 0 volunteers o n 1 4 consecutive days after taking single doses of 1 00 mg D D S are studied , together with pretreatment samples a n d urine containing standard amounts of D D S. The low est quantity of D D S st ill visually detect­ able by ELISA inhibition is 0 . 0 I Mg/ml urine. All samples obtained up to 4 1 0 days after the 1 00 mg D D S doses are positive by this method, whereas the first negative D/C results occur on the third day . The method is especially apt to monitor sub stantial failure in D D S self-administrat ion with­ out using sophisticated instruments.