Supine urethroscopic and standing cystometry as screening methods for the detection of detrusor instability.

Two hundred eighteen women undergoing multichannel urethrocystometry were also studied with supine urethroscopic cystometry and/or standing single-channel cystometry to evaluate the use of the latter two studies in screening patients at risk for detrusor instability. Thirty-one percent of the women were found to have detrusor instability on multichannel urethrocystometry. Only 24.6% of these patients were detected with supine urethroscopic cystometry, whereas 59.3% were detected with standing single-channel cystometry. The specificity of these tests was better (94.4 and 82.4%, respectively) than the above sensitivities, but analysis of their predictive values confirmed that they are both poor screening tools for populations at risk for detrusor instability.