Establishment of Reference Intervals for Biochemical Parameters in Elderly Population in a Coastal Village of South Kerala

Author(s): Gilsa Engoor Sthiandranathan1 , Miriam Varkey2 , Alan Jude Thambi3 , Deepa Maria K. Varghese4

BACKGROUND Reference intervals (RI) are one of the most common decision support tool used for interpretation of laboratory reports. Quality of the RI plays as an important role in interpretation of result and clinical decision making. RI vary with metabolic and physiological changes with advancing age. Reference intervals of Indian elderly population are not available. This study was done to see if there is any difference in the reference intervals of biochemical parameters among elderly compared to the reported value. METHODS This community based study was conducted by the Department of Biochemistry in a tertiary care teaching hospital of South Kerala. 134 apparently healthy persons above 60 years of age, using defined criteria, were recruited for the study. All the biochemical parameters of the subjects were analysed on automated analysers using standard IFCC methods using AU680 from Beckman Coulter. RESULTS The reference limits are defined as the central 95% of the population comprised between quantiles 2.5 and 97.5, leaving aside 2.5% of the individuals on both sides of the distribution and reference limits were estimated following standard methods of the International Federation of Clinical Chemistry (IFCC). The lower reference limits were estimated as the 2.5th percentile and the upper limits as the 97.5th percentile of the distribution of test results. CONCLUSIONS Establishment of age specific reference value should be done as a protocol before assuring quality control in the lab.