Establishment of dry chemistry based reference intervals of renal function test parameters for the adult population of Kaski District, Nepal

BACKGROUND: Reference intervals (RIs) for clinical chemistry test parameters are specific to the method of measurement and population under service. However, there has been no locally available dry chemistry based RIs for the Nepalese population. Thus, the present study aimed to establish dry chemistry based RIs for sodium, potassium, urea, and creatinine specific to adult populations of Kaski districts, Nepal METHODS: This was a cross-sectional study conducted at the Manipal Teaching Hospital, Pokhara, Kaski, Nepal on 360 healthy adult participants aged 18–65 years. The test parameters under study were analyzed using a fully automated OCD Vitros 350 dry chemistry analyzer following the protocols provided by the reagent kit manufacturer. The RIs were estimated using reference limits at 2.5th and 97.5th percentiles. The normal distribution of the data was tested by Kolmogorov–Smirnov, and Shapiro–Wilk tests. The differences between males and females RIs were compared by the Mann-Whitney test while age-specific RIs for each sex was compared by One-Way-ANOVA and Dunnett’s Multiple Comparisons Tests. All the data were managed and analyzed using MS Excel and SPSS version 20. RESULTS: The RIs of urea, creatinine, sodium, and potassium specific to the adult population of Kaski district, Nepal are as follows: urea: 4.20–13.70 mmol/L (males: 4.70–13.99; females: 4.20–13.23); creatinine: 44.20–106.10 μmol/L (males: 48.82–106.10; females: 35.40–83.78); sodium 135–146 mmol/L (males: 135–146; females: 135–146) and potassium 3.60–5.10 mmol/L (males: 3.54–5.0; females: 3.60–5.10). These RIs were found to be different from currently used RIs provided by the reagent manufacturer. RIs of all the test parameters were significantly influenced by the age of the study participants. However, only the RIs of urea, creatinine, and potassium were significantly influenced by sex. CONCLUSIONS: The present study has for the first time established dry chemistry based RIs for selected renal function test parameters specific to the adult population of Kaski district, Nepal. This result will aid the clinician in minimizing the errors in result interpretation and making a precise clinical decision.