Bringing the lab home: Evaluating the clinical accuracy of five urinary pH devices for stone prevention

The aim of this study was to compare the accuracy of five different manual urine pH measurement devices against the laboratory reference method.

Fresh second-morning midstream urine samples were collected from patients with a history of urolithiasis and from healthy volunteers. Measurements were performed using five different models of manual pH meters purchased from a popular general online shopping platform: Two were paper strip meters (Just Fitter and Simplex Health) and three were electronic meters (Pancellent, Yummici, and GuDoQi [QBY]). Results were compared to the reference method used in the institution's laboratory which uses the Siemens Clinitek Novus machine (Siemens AG, Munich, Germany). The degree of correlation between each device was assessed by calculating the intraclass correlation coefficient (ICC).

Seventy-two fresh urine samples were analyzed. The ICC for Just Fitter paper strip meter was 0.792 (95% confidence interval [CI] 0.685-0.865), for Simplex Health paper strip meter was 0.830 (95% CI 0.723-0.895), for Pancellent electronic meter was 0.873 (95% CI 0.804-0.919), for Yummici electronic meter was 0.866 (95% CI 0.780-0.918), and for GuDoQi electronic meter was 0.848 (95% CI 0.555-0.93).

All five urinary pH measuring tools showed good correlation with the reference method (ICC > 0.75), with electronic meters being superior to paper strips, and Pancellent brand being the closest to the reference test. According to these results, manual pH meters, especially electronic models may be considered an acceptable alternative to frequent hospital urinary pH measurements.