[Urinary pH relevance on urolithiasis management.].

Objective: Urinary pH is a factor that influences in urinary lithogenesis. It can condition the heterogeneous nucleation of calcium oxalate and the crystallization or dissolution of other substances such as uricacid, cystine and phosphates. Its exact and precise measurement is a tool to guide the treatment and prevention. The most accurate way to measure the pH is to use a glass electrode and a pH-meter, but this device is used in hospital's environment and is not portable. Test strips are not adequate for proper measurement. Recently, a portable and electronic device for measuring urinary pH has shown greater precision and accuracy in the measurement of urinary pH, with good acceptance by patients.

Method: We carried out a bibliographic search inPUBMED and EMBASE using the terms "URINARY pH", "Lithiasis", "Uro-Lihitiasis", "Urinary Stone", "Urinary pH measurement", in order to compile articles, books, abstracts and the most relevant clinical guides in English and Spanish on this topic.

Results: We select a total of 66 articles, 3 books, an abstract of a study unpublished presented at the American urology congress and the European Guidelines on urolithiasis on the effect of pH on the formation and prevention of urolithiasis. Four articles deal specifically with the effect of urinary pH on urolithiasis, 5 articles deal with a new portable electronic device for measuring urinary pH, 5 articles dealt with the measurement of urinary pH with test strips and 1 article dealt with the modification of urinary pH to reduce fouling of double J catheters, 2 articles deal about the urinary acidification with oral methionine. The selected abstract deals with the new portable device for measuring urinary pH in cystinuric patients. The 3 selected books have specific sections where the role of urinary pH in urolithiasis is discussed. Finally, in the European Urology Guidelines, the control of urinary pH is emphasized in the sections of prevention of urolithiasis formation, treatment of uric lithiasis, infectious/non-infectious phosphocalcic and cystine.

Conclusions: Urinary pH is a recognized factor in the scientific-urological community for the study, monitoring, treatment and prevention of lithiasic patients. Urinary pH measurement is a very useful tool, but test strips are not suitable for pH measurement and medical decision making. Currently, several studies have evaluated a new device to achieve the measurement of urinary pH effectively and easily by the patient, keeping urinary pH innon-lithogenic ranges with the association of medical and non-medical treatments, and good acceptability from the patients.