A-013 Analytical validation of a new troponin T assay with improved specificity: The Maastricht High Specificity Troponin T Assay

Abstract Background Cardiac troponins (cTns) are the gold standard biomarkers to diagnose non-ST-elevation myocardial infarction (NSTEMI). The introduction of high sensitive cTn (hs-cTn) immunoassays, allowed a more accurate assessment in the lower analytical range, though resulted in the frequent detection of elevated concentrations in conditions other than NSTEMI such as end-stage renal disease (ESRD). In search of a troponin assay with enhanced specificity, we developed a novel cTnT immunoassay that exclusively targets larger cTnT forms that are pathognomonic for acute cardiac injury. The aim of this study was to validate our developed Maastricht high specificity cTnT (hspec-cTnT) immunoassay on the Roche Cobas® routine clinical chemistry analyser. Methods The Limit of Blank (LoB), Limit of Detection (LoD) and Limit of Quantitation (LoQ) were determined according to the EP17-A protocol of the Clinical & Laboratory Standards (CLSI). Precision was evaluated as per the CLSI EP05-A2 protocol, for 20 days in duplicate, with 2 runs. In addition, the commercial hs-cTnT and Maastricht hspec-cTnT were assessed in patients with NSTEMI (n=25) and ESRD (n=30). Results The Maastricht hspec-cTnT assay had a LoB and LoD <3 ng/L. The CV at the lowest level of detection (3.4 ng/L) was 7.9%. The measuring range was 3-10000 ng/L, with excellent linearity (R2=0.999). Precision varied from 4.9-9.0% in the concentration range of 3.4-2758 ng/L. NSTEMI patients had both elevated median [IQR] hs-cTnT (60 [46-104] ng/L) and Maastricht hspec-cTnT (6.9 [5.0-11.3] ng/L) concentrations. Patients with ESRD had elevated hs-cTnT (41 [27-73] ng/L), but negligible Maastricht hspec-cTnT levels (3.6 [3.4-3.9] ng/L). Conclusion The novel Maastricht hspec-cTnT immunoassay demonstrated excellent analytical performance and could distinguish between cTnT elevations in NSTEMI and ESRD. The assay runs on the Roche Cobas® routine clinical chemistry analyser facilitating clinical implementation.