The Urotest AB was used to detect antimicrobial substances in urine sa
mples. Of 1022 urine specimens evaluated, Urotest AB detected inhibito
rs in 38.9%. Of 159 urine specimens from patients thought to be taking
an antibiotic, inhibitors were detected in 80.5%. This test may help
to explain culture negative urine samples from symptomatic patients, a
nd could help elucidate treatment failures and the epidemiology of ant
ibiotic resistance.