Clinical evaluation of a simple uroflowmeter for categorization of maximum urinary flow rate

Abstract

Objective: To evaluate the accuracy and diagnostic usefulness of a disposable flowmeter consisting of a plastic funnel with a spout divided into three chambers. Materials and Methods: Men with lower urinary tract symptoms (LUTS) voided sequentially into a standard flowmeter and the funnel device recording maximum flow rate (Q max ) and voided volume (V void ). The device was precalibrated such that filling of the bottom, middle and top chambers categorized maximum input flows as <10, 10-15 and > 15 ml s -1 respectively. Subjects who agreed to use the funnel device at home obtained readings of flow category and V void twice daily for seven days. Results: A single office reading in 46 men using the device showed good agreement with standard measurement of Q max for V void > 150 ml (Kappa = 0.68). All 14 men whose void reached the top chamber had standard Q max > 15 ml s -1 (PPV = 100%, NPV = 72%) whilst eight of 12 men whose void remained in the bottom chamber had standard Q max < 10 ml s -1 (PPV = 70%, NPV = 94%). During multiple home use by 14 men the device showed moderate repeatability (Kappa = 0.58) and correctly categorized Q max in comparison to standard measurement for 12 (87%) men. Conclusions: This study suggests that the device has sufficient accuracy and reliability for initial flow rate assessment in men with LUTS. The device can provide a single measurement or alternatively multiple home measurements to categorize men with Q max < 15 ml s -1 .