Analytical Discordance Between Point-of-Care Troponin Assays and a Central Laboratory High-Sensitivity Assay in a Sri Lankan Hospital Setting: Implications for Implementation

Point-of-care testing (POCT) for cardiac troponin is increasingly used to support rapid clinical decision-making, particularly in resource-limited settings. However, while many central laboratories, including those in Sri Lanka, now use high-sensitivity cardiac troponin I (hs-cTnI) assays, commonly available POCT platforms continue to use conventional methodologies with different analytical characteristics and decision thresholds. We evaluated the analytical agreement and clinical concordance of two POCT troponin assays against a central laboratory hs-cTnI assay using paired samples obtained during routine clinical care in a Sri Lankan hospital. Both POCT devices demonstrated strong correlation with the laboratory assay (Pearson r ≈ 0.90). However, Bland–Altman analysis showed substantial positive bias and wide limits of agreement, indicating poor interchangeability at the individual sample level, with proportional bias observed in one device. Clinically relevant discordance was also identified, with 26.9% and 30.4% of samples classified as negative by POCT despite being positive by the reference assay. Regression-based recalibration did not significantly improve concordance. These findings highlight that strong correlation does not ensure diagnostic agreement, emphasizing the need for local validation before integrating POCT troponin assays into established hs-cTnI diagnostic pathways.