Reference intervals of biochemical parameters in Chilean adults

Abstract

Background: Establishing reference intervals (RIs) in clinical laboratories is essential, as these can vary due to inter-individual variability as well as the analytical methods used. The purpose of this study was to determine RIs for markers and ratios biochemical in apparently healthy Chilean adults. Methods: A sample of 1,143 data was selected from the Universidad Católica de Temuco, Clinical Laboratory database, La Araucanía Region, Chile, which were analysed by sex. The Tukey's Fences was used to detect outliers and the RIs were established using the non-parametric method. Results: The RIs obtained for the female sex were: Urea 2.48-7.35 mmol/L, AST 0.20-0.69 mkat/L, ALT 0.13-1.12 mkat/L, Alkaline Phosphatase 0.83-2.5 mkat/L, Total Bilirubin 3.5-17.3 mmol/L, Direct Bilirubin 1.5-4.9 mmol/L, Uric Acid 148-362 mmol/L and Total Proteins 66.3-80.3 g/L and for males: Urea 3.28-8.17 mmol/L, AST 0.22-0.80 mkat/L, ALT 0.18-1.9 mkat/L, Alkaline Phosphatase 0.93-2.33 mkat/L, Total Bilirubin 4.58-24.0 mmol/L, Direct Bilirubin 1.9-7.5 mmol/L, Uric Acid 202-458 mmol/L and Total Proteins 67.4-83 g/L. The FIB-4 and APRI index presented a range of 0.2-1.6 and 0.12-0.5 respectively (in both genders) and the AST/ALT index was 0.5-2 in women and 0.38-1.66 in men. Conclusion: A panel of RIs for locally-relevant biochemical parameters has been established, this study being the first to be carried out in our country. When comparing these results with other studies and those reported by reagent manufacturers, some differences were observed. This study thus contributes to increase the reliability in the interpretation of laboratory results and therefore to the clinical management of patients.