EFFECT OF BETA-GLUCURONIDASE ON URINARY BENZODIAZEPINE CONCENTRATIONSDETERMINED BY FLUORESCENCE POLARIZATION IMMUNOASSAY

In samples from patients treated with oxazepam, beta-glucuronidase inc reased the immunoreactivity of urinary benzodiazepines analyzed by flu orescence polarization immunoassay (FPIA). Increasing concentrations o f beta-glucuronidase added to samples from drug-free controls did not influence the results. In the absence of beta-glucuronidase, 22 of 35 samples from patients undergoing detoxification gave positive results at a cutoff concentration of 200 mu g/L. Pretreatment with beta-glucur onidase increased the number of drug-positive samples to 33. The drug- negative samples were obtained from two patients who had been oxazepam -free for at least 1 week. Thus, beta-glucuronidase can be used to inc rease the sensitivity of the urinary benzodiazepine FPIA without reduc ing the specificity of the method.