1 GRC n°20, Groupe de Recherche Clinique sur la Lithiase Urinaire, Sorbonne Université , AP-HP, Hôpital Tenon, Paris, France .
2 Department of Urology, AZ Klina, Brasschaat , Belgium .
J Endourol. 2018 Jul;32(7):647-652. doi: 10.1089/end.2018.0202. Epub 2018 May 29.
To evaluate a portable electronic pH meter and to put its accuracy in perspective with reagent strips read by a layperson, a healthcare professional, and an electronic reading device.
Based on a preanalysis on 20 patients, a sample size of 77 urine aliquots from healthy volunteers was necessary to obtain sufficient study power. Measurements of urinary pH were obtained by use of reagent strips, a portable pH meter and a laboratory pH meter (gold standard). Reagents strips were read by a professional experienced in interpreting strips, a layperson, and an electronic strip reader. The mean matched pair difference between measurement methods was analyzed by the paired t-test. The degree of correlation and agreement were evaluated by the Pearson's correlation coefficient and Bland-Altman plots, respectively.
The mean matched pair difference between the gold standard and all other pH measurement methods was the smallest with the portable electronic pH meter (bias 0.01, 95% confidence interval [CI] -0.07 to 0.08; p = 0.89), followed by strips read by a professional (bias -0.09, 95% CI -0.21 to 0.02; p = 0.10), layperson (bias -0.17, 95% CI -0.31 to -0.04; p = 0.015), and electronic strip reader (bias -0.29, 95% CI -0.41 to -0.16; p < 0.001). The portable electronic pH meter achieved the highest Pearson's correlation coefficient and narrowest 95% limits of agreement, followed by strip interpretation by a professional, electronic strip reader, and layperson. To quantify the ability of pH measurement methods to correctly classify values within a predefined urinary pH target range, we performed classification tests for several stones. The portable electronic pH meter outperformed all other measurement methods for negative predictive values.
Findings of this study support that the portable electronic pH meter is a reliable pH measuring device. It appears to be more accurate compared to reagent strips readings.
评估一款便携式电子 pH 计，并将其与由非专业人士、医疗专业人员和电子读数设备读取的试剂条的准确性进行比较。
基于对 20 名患者的预分析，需要 77 份来自健康志愿者的尿液样本才能获得足够的研究效力。使用试剂条、便携式 pH 计和实验室 pH 计（金标准）测量尿液 pH 值。专业解读试剂条的人员、非专业人士和电子条阅读器分别读取试剂条。通过配对 t 检验分析测量方法之间的平均配对差值。通过 Pearson 相关系数和 Bland-Altman 图分别评估相关性和一致性。
金标准与所有其他 pH 测量方法之间的平均配对差值最小的是便携式电子 pH 计（偏差 0.01，95%置信区间 [CI] -0.07 至 0.08；p = 0.89），其次是专业人员读取的试剂条（偏差 -0.09，95% CI -0.21 至 0.02；p = 0.10）、非专业人士（偏差 -0.17，95% CI -0.31 至 -0.04；p = 0.015）和电子条阅读器（偏差 -0.29，95% CI -0.41 至 -0.16；p < 0.001）。便携式电子 pH 计获得了最高的 Pearson 相关系数和最窄的 95%置信区间，其次是专业人员解读试剂条、电子条阅读器和非专业人士。为了量化 pH 测量方法正确分类预设尿液 pH 目标范围内值的能力，我们对几种结石进行了分类测试。便携式电子 pH 计的阴性预测值优于所有其他测量方法。
本研究结果支持便携式电子 pH 计是一种可靠的 pH 测量设备。与试剂条读数相比，它似乎更准确。
