“COMPARISON OF COVERAGE INTERVAL WITH REFERENCE INTERVAL FOR SOME COMMON LABORATORY ANALYTES IN A TERTIARY CARE HOSPITAL OF KOLKATA”

Dr. Indranil Chakraborty, Dr. Sanghamitra Chakraborty*, Dr. Chinmoy Ghosh, Dr. Sharmistha Chatterjee and Dr. Mayukh Chakraborty

ABSTRACT

The reference intervals serve as sheet anchor in clinical diagnosis. The reference intervals of laboratory analytes differ from one population to another due to differences in age, gender, genetic make-up, dietary habits, ethnicity, life style and socio-economic strata. The objective of this study is to compare the „coverage interval‟ obtained from the few reference values with that of „reference interval‟ calculated from 120 reference values.This study has been undertaken to establish coverage interval of some common analytes with 71 study subjects in Bengali population and to highlight the presence of differences if any with reference intervals using 120 subjects as per IFCC guidelines.Analysis of the analytes was done using automated and semi-auto analyser. The values of biochemical parameters were analysed using IBM SPSS 16 statistical software. The determination of reference interval of the anaytes is a priori for “good laboratory practice”. The coverage interval obtained were 103-217 mg/dl, 27-44 mg/dl and 56-163 mg/dl for total cholesterol, high density lipoprotein cholesterol and triacyglycerol respectively. While on the other hand there was no significant difference (p>0.05) of mean values for glucose for the study subjects used for coverage interval and reference interval estimation. But the upper limit was 5.6mmol/L lower than the theoretical cut-off of 6.1mmol/L for diabetes diagnosis. This implies that pre-diabetic in Indian population is increasing which is indeed the truth. Moreover, both reference interval and coverage interval of liver enzymes, bilirubin was quite different from the reporting interval in literatures.

Keywords: Reference values, reference interval, coverage interval.