Reference Interval of Serum Cystatin C in Dravidian Population Subset of South Asian Ethnic Groups: An Observational Cross-sectional Study
Published: October 1, 2022 | DOI: https://doi.org/10.7860/JCDR/2022/58894.16965
Shajee Sivasankaran Nair, K Geetha Damodaran, Sestin Sebastian
1. Associate professor, Department of Biochemistry, Government Medical College, Manjeri, Kerala, India.
2. Professor, Department of Biochemistry, Government Medical College, Thrissur, Kerala, India.
3. Senior Resident, Department of Biochemistry, Sree Narayana Institute of Medical Sciences, Chalakka, Kerala, India.
Correspondence
Dr. Sestin Sebastian,
Senior Resident, Department of Biochemistry, Sree Narayana Institute of Medical Sciences, Chalakka, Kerala, India.
E-mail: sestinsebastian19@gmail.com
Introduction: Serum Cystatin C (Cys C) facilitates to detect mild renal dysfunction and overall risk of death in older patients with chronic renal diseases. The requirement for creating a particular reference interval is mandatory for such renal diseases in South Asian population since the value of serum creatinine varies largely with age, gender and population/ethnicity and data of same is short for South Asian population.
Aim: To determine the reference interval of serum Cystatin C amongst the Dravidian population subset of South Asian ethnic groups.
Materials and Methods: This observational cross-sectional study was conducted in Department of Biochemistry and Transfusion Medicine at Government Medical College, Thrissur, Kerala, India, from July 2020 to January 2021 among on 235 healthy adults (20-60 years). A 4 mL of blood was drawn by aseptic precautions and serum was separated within three hours of blood collection. Serum Cys C was assayed by latex enhanced immunoturbidimetric cystatin C assay using a calibrator traceable to international standard European Specific Protein Reference Material (ERM DA-471) developed by the International Federation of Clinical Chemistry (IFCC) and Laboratory Medicine. Serum Creatinine (sCr) by Jaffe method in a fully automatic clinical chemistry analyser was assessed. Categorical variables are presented using frequency (percentage) while continuous variables are summarised with an interpercentile range. The Kolmogorov-Smirnov test was used to assess the normality of the distribution of continuous variables.
Results: Total of 235 subjects (20-60 years of age with 17 males and 218 females) were included in the study. The non parametric reference intervals for Cys C were found to be from 0.39 to 0.79 mg% and that of sCr ranged from 0.79 to 1.2 mg%. The relationship between Cystatin C with age showed an increase in Cystatin C levels as age advances; Spearman’s rank correlation coefficient (rho=0.197). The weak correlation between Cystatin C and sCr was also observed (rho=0.37; p-value <0.0001).
Conclusion: The level of serum cystatin C (0.39 to 0.79 mg%) can be used as a diagnostic concentration reference interval of the protein that helps to recognise, standardise and establish it as a potential biomarker to detect renal disorders in South Asian ethnic population.
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