Could conductivity be used as a parameter in urinalysis?

Conductivity is a non-linear function of electrolyte concentration in solutions and could be used as an indirect method. The aim of this study was to determine the feasibility of urine conductivity measurement, which is a simple, cheap and not time consuming method, in the evaluation of renal functions. Seventy-two patients whose primary diseases were not taken into consideration were enrolled in this study. First morning urine specimens were obtained from all the patients and evaluated for osmolality, conductivity, pH, specific gravity, protein, creatinine, urea, uric acid, glucose, sodium, potassium, chloride, inorganic phosphate and calcium levels. There was a significant positive relation between osmolality and creatinine, urea, sodium, potassium, chloride, inorganic phosphate, uric acid, conductivity and specific gravity. Conductivity was also determined to be positively related to osmolality (r: 0.390, p < 0.01), sodium (r: 0.326, p < 0.01) and uric acid (r: 0.345, p < 0.01). The patients were grouped as those with a urine osmolality of less or more than 290 m Osm/kg. H2O (group A and B respectively). Urine conductivity was 6.84 +/- 5.35 (0.16-23.2) mScm-1 in group A and 10.6 +/- 5.25 (0.12-192) mScm-1 in group B. The difference was statistically significant (p = 0.005). When the spectrum of conductivity values were evaluated separately in each group, 74% of the patients in group A and 33.9% of the patients in group B were determined to have a conductivity level of less than 7.338 mScm-1. In conclusion, urine conductivity has a positive relation with osmolality. In addition, while osmolality and specific gravity are effected by many non-electrolyte molecules, conductivity is only related to sodium and uric acid concentrations. In addition, urine osmolality and conductivity levels could be used to interpret the concentration of uncharged glucose molecules. These results suggest that conductivity could be used as a parameter in routine urinalysis.