Laboratory diagnosis of renal failure: urine conductivity and tubular function.

AIM: Conductivity is a measure of a material's ability to conduct an electric current and it works thanks to movable charges. Conductivity in urine is directly proportional to ionic contents. The aim of this study was to evaluate the significance of urine conductivity by using the Sismex UF-100 analyser in correlations with other surrogate parameters of osmolality and renal diuresis, relative density, electrolytes and creatinine concentration. METHODS: For this study 140 urine samples were submitted for diagnostic urinalysis to the Clinical Pathology laboratory. Samples were collected from 70 healthy subjects, 42 diabetics with poor metabolic control and significant glicosuria, 28 patients with monoclonal gammopathy of uncertain significance, with significant proteinuria. All the samples were assessed for conductivity (UF-100 Sysmex), relative density (refract meter Zeiss), sodium, potassium, chlorine, creatinine, urea, glucose, protein (Olympus AU-2700). RESULTS: Urine conductivity appears to be related to ionic concentration but not to glucose and/or protein presence. CONCLUSIONS: This study results suggest that conductivity determination should be useful in diabetic patients to study the tubular function minimising interferences due to osmotic action of glucose.