Most current POCT cardiac troponin assays, which are typically less sensitive than the more widely used central laboratory assay, require repeat sampling 3 to 6 hours post-admission to adequately rule out myocardial injury. In contrast, central laboratory cardiac troponin assays are highly sensitive and therefore require typically only 1-3 hours serial testing for ruling out myocardial infarction. Cardiac troponin assays measure either troponin T or cardiac troponin I, each with different cut-offs for ruling out myocardial infarction. Even when measuring the same form of troponin, differences in assay methodologies and manufacturers-specific cut-offs can lead to discrepancies between central laboratory and POCT results. The discrepancies could complicate the accurate interpretation of the rise and fall of troponin changes, potentially affecting clinical decisions such as risk stratification and treatment strategies. Therefore, a committee of clinicians and laboratorians should develop a testing algorithm for manufacturer-specific POCT troponin that reflects the specific methodology used.
Sources:
Apple FS, et al. Implementation of high-sensitivity and point-of-care cardiac troponin assays into practice: some different thoughts. Clin Chem. 2021;67(1):70-78. PMID: 33279984.
Kavsak PA, et al. Imprecision of high-sensitivity cardiac troponin assays at the female 99th-percentile. Clin Biochem. 2024;125:110731. PMID: 38360198.
Ungerer JPJ, et al. Discordance with 3 cardiac troponin I and T assays: implications for the 99th percentile cutoff. Clin Chem. 2016;62(8):1106-14. PMID: 27335076.