RESUMO
It is a fact that recurrence of urinary stones is a common medical problem. One of the key factors used in determining the risk of urinary stone-formation is the urine relative saturation in the major constituents of lithiasis. Nomograms were developed in the 1970's to estimate the relative saturation of urine. We present here easy-to-use mathematical equations derived from these nomograms. These equations can be integrated directly in the LIS of any laboratories, and can be used as a tool in the treatment and prevention of recurrent stone-formation.
Assuntos
Cálculos Renais/química , Modelos Biológicos , Cálculos Urinários/urina , Algoritmos , Amônia/urina , Cálcio/urina , Oxalato de Cálcio/análise , Fosfatos de Cálcio/análise , Cisteína/urina , Cistina/análise , Hospitais Urbanos , Humanos , Concentração de Íons de Hidrogênio , Magnésio/urina , Ácido Oxálico/urina , Fosfatos/urina , Quebeque/epidemiologia , Recidiva , Indução de Remissão , Fatores de Risco , Estruvita/análise , Ácido Úrico/análise , Cálculos Urinários/epidemiologia , Cálculos Urinários/terapiaRESUMO
There is yet to be a reliable prediction of urolithiasis. To facilitate early diagnosis, a simple and rapid high performance liquid chromatography method with electrochemical detection using disposable copper-nanoparticle-plated electrodes (Cu(n)-SPE) was developed for multiple detection of creatinine and 4 urolithic organic acids. A total of 206 normal and urolithic human and canine urines and urolith samples were collected for direct analysis of creatinine, cystine, uric acid, oxalic acid, and citric acid without sample cleanup and derivatization processes. Urinary organic acids were separated in 11 min and were devoid of ascorbic acid interference. The detection limits (S/N>3) were at the nanomolar level with linear dynamic ranges spanning 2-3 orders of magnitude. Recoveries in urine ranged from 99.5% for creatinine to 86.5% for citric acid. The analytical variations (RSD) were less than 6.2% in phosphate buffer and 7.7% in urine. Important differences in organic acid levels/profiles between animal species and among normal and urolithic urines/urolith were unveiled and corresponded well (70-90%) with the urolithic risk in a retrospective assessment. The simplicity and reproducibility of this method using disposable Cu(n)-SPE has made routine urine analysis possible and can be of great clinical and diagnostic potential in the screening of urolithiasis and abnormal states related to excess secretion of organic acids and amino acids in humans and animals.