Reference intervals (RI) are the most common decision support tool used for interpretation of numerical laboratory reports. The quality of the RI can play as large a role in result interpretation as the quality of the result itself. As such there is hardly any study examining RI for liver specific biochemical parameters in Indian population especially north Indians having drastically different food habits as compared to rest of the India. So there is a need to establish the RI for north Indian population. Present study was conducted on 2,021 apparently healthy individuals of north Indian origin ranging in age from 15-60 years, were selected randomly using defined criteria. Lipemic, hemolysed, icteric and stored samples were also excluded adopting preanalytical criteria for rejection of sample. Non parametric methodology for determination of RI was adopted as most of the biochemical parameters included revealed non Gaussian distribution. Data were analyzed for middle 95 percentile (2.5th-97.5th percentile), median and 95 % confidence interval using SPSS software package version 10.0. The upper and the lower limit of RI (reported Vs observed) for bilirubin (0-1.2 Vs 0.30-1.30 mg/dL), serum glutamate oxaloacetate transferase (SGOT) (0-41 Vs 13-52.80 IU/L), serum glutamate pyruvate transferase (SGPT) (0-50 Vs 10-68 IU/L) showed wide variation as compared to reported standard RI however Gamma glutamyl transferase (GGT) (0-50 Vs 5.00-50.60 IU/L) remained within the reported standard RI. Further gender wise evaluation revealed higher cutoff in males (AST 14-55, ALT 11-70.35, GGT 6.76-51.09 in IU/L, bilirubin (0.40-1.34 mg/dL) as compared to females (SGOT 13-50.43, SGPT 9-63.43, GGT 3.92-48.70 in IU/L, Bilirubin 0.30-1.20 mg/dL) for both enzymatic and non enzymatic biochemical parameters. The variations may be attributed to dietary pattern smoking and alcoholism.
Keywords: Liver specific biochemical parameter; Observed value; Reference interval; Reported value.