We described a chemiluminescent immunoassay (CIA) for 5 alpha-androstane-3 alpha, 17 beta-diol-glucuronide (3 alpha-diol-G) in human diluted urine. This method allowed the direct measurement in 1 microliter of urine avoiding the hydrolysis and extraction steps for sample pretreatment commonly used in routine methods. The hapten 3 alpha-diol-G was synthesized by a Koenigs-Knorr reaction. The immunogenic complex, 3 alpha-diol-G conjugated to bovine serum albumin (BSA), was employed to induce the formation of specific antibodies in New Zealand rabbits. In addition, the required chemiluminescent (CL) tracer was prepared. The characteristics of the antibody was determined as regard to specificity and sensitivity and the precision of the assay methods established. In 22 hirsute women affected by polycystic ovarian syndrome we found 3 alpha-diol-G values significantly (p less than 0.01) higher (146.28 +/- 73.77 micrograms/g of creatinine; mean +/- SD) than those observed in normal women (72.1 +/- 32.58 micrograms/g of creatinine; mean +/- SD).