Simultaneous Comparison of the Measurement Accuracy of a Developed Scale-type Uroflowmeter with That of Three Medical Uroflowmeters in Young Males

Urine-related information, such as voided volume and flow rate, is important for the diagnosis of dysuria. Uroflowmeters, which are used for obtaining urine information, measure mainly the weight gain of the collection cup or the rotation of the impeller. These devices pose hygiene-related problems because of the contact between urine and the device. In addition, the patients are forced to urinate in unfamiliar environments and positions, which can lead to unusual results. Therefore, there is a need for a non-contact uroflowmeter that can measure urine information in an environment and a posture to which the user is accustomed. A uroflowmeter that measures the rise of the water level in the toilet bowl is also available; however, it requires extensive installation. To address these problems, we have developed a scale-type uroflowmeter that measures weight loss during standing urination. The purpose of this study was to evaluate the measurement accuracy of our developed scale-type uroflowmeter. For this purpose, human urination was measured simultaneously using the developed uroflowmeter and three different medical uroflowmeters (Freeflow®, P-Flowdiary®, and PicoFlow2®), to compare the voided volume, maximum flow rate, and average flow rate. The results of the developed uroflowmeter showed good agreement with the weight of urine measured by an electronic balance and the voided volume measured by the medical uroflowmeters. The error rates between the true voided volume measured by the electronic balance and the four uroflowmeters ranged from 0.9% to 22.5%. Comparing the maximum and average flow rates of the three medical uroflowmeters with the scale-type uroflowmeter, the error rates ranged from 9.4% to 25.4% and 17.4% to 25.2%, respectively.