Aim: The measurement uncertainty (MU) of high-sensitivity troponin T (hs-TnT) and myoglobin assays was calculated in accordance with ISO/TS 20914:2019. The calculated MU values were subsequently compared with the relevant analytical performance specifications (APS).

Materials and Methods: Internal quality control (IQC) and external quality control (EQC) data collected between January and June 2024 were analyzed. Level 1 and Level 2 control materials for hs-TnT and myoglobin were measured daily. Expanded combined relative measurement uncertainty (Ucrel) were calculated with calibrator uncertainties included, and level-specific estimates were combined to derive the total device-level expanded measurement uncertainty, t(Ucrel).

Results: For the hs-TnT assay, Ucrel values at Level 1 exceeded the allowable APS on both the Cobas 8000 and Cobas Pro analyzers, whereas Level 2 results remained within acceptable limits. t(Ucrel) values on both analyzers (19.63% and 14.24%) exceeded the minimum APS of 13%. For myoglobin, Ucrel values were below the APS limit of 13% at both control levels on the Cobas 8000 analyzer, whereas they slightly exceeded the APS at both levels on the Cobas Pro analyzer. Accordingly, the t(Ucrel) value exceeded the APS on the Cobas Pro analyzer (13.45%) but remained acceptable on the Cobas 8000 analyzer (11.49%).

Conclusion: Routine monitoring and reporting of MU can facilitate more reliable interpretation of laboratory results, particularly those close to clinical decision thresholds. Improved communication of MU between laboratories and clinicians may enhance the clinical utility of cardiac biomarkers and support more informed diagnostic decision-making.