Reference intervals for serum creatinine and urea in the adult western Sudanese population

Abstract

Introduction: Serum creatinine and urea levels are affected by numerous factors such as ethnicity, environment, age, sex, and  anthropometric measurements. The Clinical and Laboratory Standards Institute (CLSI) recommends that each laboratory should establish  its own reference intervals for biochemistry and haematology. There are no local reference intervals for serum creatinine and  blood urea in Sudan; instead, intervals derived from worldwide research are used. The purpose of this study was to determine the blood  urea and serum creatinine reference intervals for healthy adults in the Western Sudanese population. Method: Randomly selected adult Sudanese residents of Al Fashir City who were from the Western Sudan states of Kordofan and Darfur  were the subjects of a cross-sectional study conducted in September and October 2018. We recruited 153 participants. After giving their  consent, they were evaluated using a questionnaire that collected medical history and demographic information. We used standard  techniques to measure blood pressure, body mass index, urea, and creatinine. Kolmogorov-Smirnov tests were used to assess the  distributions of the creatinine and urea values, and reference intervals calculated. T-tests were used to investigate differences of mean  creatinine and urea levels by sex and age. IBM SPSS Statistics version 25 was used to analyse the data and p ≤ 0.05 was considered  significant. Results: Overall, the reference intervals (Mean±1.96*SD) for serum creatinine and urea levels were 0.45-0.92 mg/dL and  7.6-27.9 mg/dL respectively, compared to international reference intervals adopted from the American Board of Internal Medicine (ABIM)  serum creatinine (males 0.7-1.3, females 0.5-1.1 mg/dL) and blood urea (17.12-42.8 mg/dL for both sexes) and The Western Sudanese  population’s mean serum creatinine and urea levels were, respectively, 0.69 mg/dL and 17.8 mg/dL. Male sex was associated with higher levels of both creatinine and urea (p<0.001). Conclusion: This study documented lower reference intervals for creatinine and urea in the  Western Sudanese population.