Determination of 99th percentile upper reference limit of cardiac troponin I in healthy population of Rahim Yar Khan.

Objective: To determine the 99th percentile upper reference limit (URL) of cardiac troponin I (cTnI) in healthy population of Rahim Yar Khan. Study Design: Cross-sectional study. Setting: Department of Chemical Pathology, Sheikh Zayed Hospital, Rahim Yar Khan. Period: February 2023 to November 2023. Methods: A total of 262 healthy individuals aged between 20-76 years without any known cardiac diseases were included and selection was performed on the basis of a designed questionnaire. Serum hs-cTnI was measured using a chemiluminescent technique on ACCESS II, Beckman Coulter. A non-parametric statistical technique was used to establish the 99th percentile upper reference limit (URL) of hs-cTnI in accordance with CLSI Document C28-A3c. Mann Whitney U test was applied between two subgroups taking p value <0.05 as significant. Results: In this study, 136 (51.9%) were males and 126 (48.1%) were females. Of the total 262 study subjects, 180(68.7%) had values greater than Limit of detection (LoD) 2.3 ng/L while 82(31.3%) had values less than LOD. Overall, Male and Female 99th percentile URL of hs-cTnI in population of Rahim Yar Khan was found to be 10.8, 13.1 and 8.3 ng/ml respectively before removing any outliers. After removing outliers by Dixon/Reed method, the 99th percentile URL found to be 8.4, 9.0 and 6.3 ng/L for overall, males and females respectively. The distribution troponin I with respect to age and gender was statistically significant with p value <0.05. Conclusion: On the basis of our study, it was concluded that the study population's overall high-sensitive cardiac troponin I 99th percentile URL was found to be significantly lower than both manufacturer-quoted values and results published in prior publications. High-sensitive troponin assay allows precise quantification of very low cardiac troponin concentration that helps in rapid exclusion of myocardial infarction.