Reference Intervals of Certain Liver Specific Biochemical Analytes in Indian Population

Abstract

Dear EditorMost of the laboratories, all over the world consider thatReference Intervals (RI) in vogue are either inaccurate orin-appropriate for the population they serve and needsupdation. The IFCC has also stressed upon that everylaboratory must have their own set of reference limits. Therecent Clinical and Laboratory Standards Institute (CLSI)/International Federation of Clinical Chemistry (IFCC)document is an excellent aid for design and implementationof such studies [1]. Most of the laboratories in India followRI available in literature which is based on Western pop-ulation. These RI can be questioned because of differencesarising due to variations in diet, life style and environ-mental conditions and ethnicity related variations. There ishardly any documentation regarding RI of liver specificbiochemical parameters in North Indian population. Inview of this, we examined RI of liver specific biochemicalanalytes in North Indian population using IFCC/CLSIguidelines [1].The present study was conducted on 2,021 apparentlyhealthy individuals of North Indian origin ranging in age20–60 years selected randomly using defined criteria, outof which 494 were excluded using appropriate exclusioncriteria defined by IFCC and NCCLS [1]. Finally 1,527individuals were included in present study.After an overnight fasting, venous blood was drawnfrom antecubital vein using aseptic technique. Sampleswere analysed for liver specific biochemical parametersusing standard methods on fully autoanalyzer OlympusAU–400 after proper standardization with the help of cal-ibrators and quality of tests was ensured by using internaland external quality controls. Data were analyzed formiddle 95 percentile (2.5th–97.5th percentile), median and95% confidence interval using SPSS software packageversion 10.0 [4].The results of our study are depicted in the Table 1 asshown below.The upper and lower limit of RI (Reported vs. Observed)for Bilirubin (0–1.2 vs. 0.30–1.30), SGOT (0–40 vs.13–52.80), SGPT (0–50 vs. 10–68), ALP (110–310 vs.107–361.80) showed wide variation as compared to repor-ted standard RI while GGT (0–50 vs. 5.00–50.60) which isrelated to biliary disease and marker for alcoholismremained within the reported standard RI. For both enzy-matic and non enzymatic biochemical parameters uppercutoff value was greater in males (SGOT 14–55, SGPT11–70.35, GGT 6.76–51.09, Bilirubin 0.40–1.34) as com-pared to females (SGOT 13–50.43, SGPT 9–63.43, GGT3.92–48.70, Bilirubin 0.30–1.20) (Table 1). Our findingsare though consistent with studies conducted in south Indianpopulation by Sultana et al. and Ashavaid et al. to the extentthat upper cut off for most of the parameters was higher thanthe reported RI. However cut off for SGOT, SGPT and GGTin present study was lower as compared to values reportedby Sultana et al. [2]and Ashavaid et al. [3]. The variations infindings may be attributed to differences in size and habitat(rural/urban) of reference population, dietary habits, lifestyle and climatic conditions.With respect to age a progressive narrowing of referenceinterval of bilirubin was observed, this may be attributed to