Category: Clinical Stones: Medical Management

MP10-2 - Evaluation of a portable urinary pH meter and reagent strips

Fri, Sep 21
2:00 PM - 4:00 PM

Introduction & Objective :

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.


Methods :

Based on a pre-analysis 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.


Results :

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% 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, the electronic strip reader and the layperson. In order 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.


Conclusions : Findings of the current study support that the portable electronic pH meter is a reliable pH measuring device. It seems to be more accurate compared to reagent strips readings.

Vincent De Coninck

Urologist
AZ Klina
Brasschaat, Antwerpen, Belgium

Vincent De Coninck graduated as a medical doctor from the Free University of Brussels, Belgium (VUB) in 2011. He became a certified urologist in 2017 after a training at the University Hospital of Brussels (Prof. Dr. Dirk Michielsen) and OLV Aalst (Prof. Dr. Alex Mottrie), where he developed a special interest in the minimal invasive treatment of benign and malignant pathologies. In the same year, he became Fellow of the European Board of Urology.
In 2018, he completed a one-year fellowship program of the Endourological Society in Paris, France under the supervision of Prof. Dr. Olivier Traxer. During that fellowship, he also obtained a diploma in urolithiasis, organized by Dr. Michel Daudon at the Sorbonne University in Paris, France. Afterwards, he was trained in HoLEP by Dr. Karin Lehrich in Berlin, Germany.
Currently, he is completing a three-month fellowship under the supervision of Dr. Guido Giusti in Milan, Italy. In December 2018, he will start working as an endourologist in AZ Klina, Brasschaat, Belgium. He will focus on the medical and surgical treatment of kidney stones and benign prostatic obstruction (HoLEP) and he will continue publishing articles relating to the management of patients with renal stone disease.

Etienne X. Keller

Fellow of the ES
Sorbonne Université, GRC n°20, Groupe de Recherche Clinique sur la Lithiase Urinaire, AP-HP, Hôpital Tenon, F-75020 Paris, France
Paris, Ile-de-France, France

Maria Rodriguez-Monsalve Herrero

Urologist
University Hospital Puerta de Hierro, Majadahonda.
Majadahonda, Madrid, Spain

Steeve S. Doizi

Urologist
Sorbonne Université, GRC n°20, Groupe de Recherche Clinique sur la Lithiase Urinaire, AP-HP, Hôpital Tenon, F-75020 Paris, France
Paris, Ile-de-France, France

Jean-Philippe Haymann

Sorbonne Université, Service d’Explorations Fonctionnelles, Institut National de la Santé et de la Recherche Médicale, UMR_S1155, AP-HP, Hôpital Tenon, F-75020 Paris, France
Paris, Ile-de-France, France

Olivier O. Traxer

Professor
Sorbonne Universite, GRC n020 Lithiase Renale, AP-HP, Hospital Tenon, F-75020 Paris, France
Paris, Ile-de-France, France