Quantification of cough-related urine loss using the paper towel test.

OBJECTIVE: To develop and test a simple and rapid method for quantifying the urine loss resulting from three deep coughs using an ordinary brown paper towel.
METHODS: A brown paper towel is held lightly against the perineum during three single coughs performed in the upright stance. The resulting wetted area was calculated using simple geometry; if desired, leakage volume can be interpolated from a calibration curve, which demonstrates the relationship between wetted area (cm2) and volume (mL) of leakage. Four bench tests of the method were performed. In addition, the test-retest reliability of the method was evaluated in eight elderly women with mild stress urinary incontinence, a sample size adequate to detect a 1-mL difference with 80% power.
RESULTS: The smallest measurable quantity of fluid resulted in a wetted area of 0.04 cm2 (equivalent to 0.2 microl). For leakage volumes up to 6 mL, the regression showed that each 1 mL of fluid volume resulted in an average 25.4 cm2 increase in wetted area (coefficient of determination: 0.97). In eight women with stress incontinence 95% of within- and across-visit comparisons of urine loss were within 1 mL.
CONCLUSION: The paper towel test is a simple and reliable measure providing immediate visual and quantitative feedback of cough-related urine loss typical of mild-to-moderate stress urinary incontinence.