Reference Interval of Serum Gastrin 17 (G-17) for Healthy Population: A Non-Invasive Screening Biomarker for Gastric Disorders.

Objective: To analyse fasting serum concentrations of G-17 in healthy individuals to establish the reference intervals (RIs) in the Pakistani population.
Study Design: Cross-sectional, observational study. Place and Duration of the Study: Department of Clinical Chemistry and Immunology, Chughtai Institute of Pathology, Lahore, Pakistan, from October to December 2022.
Methodology: Fasting serum samples from one hundred and twenty healthy individuals between the age of 18-65 years were collected according to the CLSI recommendations after taking written informed consent. Samples were analysed on the auto-analyser for the quantitative measurement of serum G-17 by sandwich chemiluminescence immunoassay. Kolmogorov-Smirnov test was applied to check normality. A p-value of <0.05 was considered significant; 2.5th and 97.5th percentiles were computed using the formula 0.025 (n+1) and 0.0975 (n+1), respectively.
Results: Of the 120 samples, 74 were obtained from male patients and 46 from females. The mean age was 30.2 ±10.36 years. The histogram revealed a non-parametric distribution of the data. The established reference intervals by the rank-based method were 2.31 pg/mL and 49.36 pg/mL which corresponds to 2.5th and 97.5th percentiles, respectively. These were markedly different from the Chinese reference ranges.
Conclusion: Ethnic and geographic variations affect the trends of RIs of Serum G-17. There is a need to establish its population-specific RIs for G-17, so it can be used as a non-invasive option in identifying patients requiring invasive endoscopic intervention.
Key Words: Gastrin, Atrophic Gastritis, Biomarker, Reference values.