The Pyridium pad test for diagnosing urinary incontinence. A comparative study of asymptomatic and incontinent women.

Eighteen women with urodynamically proven genuine stress incontinence awaiting surgery and 23 normal, asymptomatic, continent female volunteers took part in a study to compare the accuracy of a qualitative pad test with a quantitative pad-weighing test in detecting urine loss. Each woman took 600 mg of phenazopyridine hydrochloride (Pyridium, Parke-Davis) in three equally divided doses over 18-24 hours and then underwent a standardized, one-hour pad test as described by the International Continence Society. The Pyridium pad test was regarded as positive if there was any orange staining on the pad. The quantitative pad-weighing test was considered positive if there was a weight gain of 1.0 g or more at the end of the one-hour test period. All 18 patients with genuine stress incontinence had positive Pyridium pad tests, and all had pad weight gains of greater than or equal to 1.0 g (mean, 16.5). The maximum pad weight gain in the asymptomatic, continent volunteers was 0.7 g (mean, 0.1), and none was aware of any urinary leakage during the test; however, 12 (52%) had positive Pyridium pad tests. The Pyridium pad test appears 100% sensitive in detecting urine loss in symptomatic women with genuine stress incontinence, but it has a high false-positive rate in healthy, asymptomatic, continent women. If pad-weighing tests are done, the addition of Pyridium generally will not be useful, and if Pyridium is used by itself, the results may be misleading.