Diagnostic performance of Mindray CL1200i high sensitivity cardiac troponin I assay compared to Abbott Alinity cardiac troponin I assay for the diagnosis of type 1 and 2 acute myocardial infarction in females and males: MERITnI study

Objectives: We examined the 0- and 2-h diagnostic performance of the Mindray high-sensitivity cardiac troponin I (hs-cTnI) assay using two predefined sex-specific 99th percentile upper reference limits (URL) in patients with normal electrocardiograms to aid in the diagnosis of myocardial infarction (MI). Methods: Consecutive emergency department patients undergoing serial high-sensitivity cardiac troponin I (hs-cTnI) testing on clinical indication were studied in the 'Mindray hs-cTnI Assay Analytical and Clinical Evaluation for the Diagnosis and RIsk Assessment of Myocardial InfarctIon' (MERITnI) trial (NCT05853042). Plasma hs-cTnI testing was performed using Mindray CL1200i (investigational) and Abbott Alinity (clinical) assays. Results: In 1,556 patients (60.7% male, 43.3% White, 45.8% Black, 34.8% chest pain), 2.7% had type 1 MI, 2.7% type 2 MI, and 21.5% non-MI myocardial injury. At 0h for all MIs (n=86), using package insert URLs and Universal Sample Bank (USB) URLs, sensitivities were 83.7 and 93.0%. At 0/2h for all MIs with package insert and USB URLs, sensitivities were higher with serial testing, at 95.3 and 97.7%. Negative predictive value (NPVs) were excellent and similar for both URLs, ranging from 98 to 100%. Substantial hs-cTnI concentration differences were observed between sex and injury types. Alinity hs-cTnI diagnostic observations were similar for both package insert and USB URLs. Conclusions: The Mindray CL1200i hs-cTnI assay provides the relevant clinical diagnostic information to enable clinicians to deliver cost-effective care for patients to aid in the diagnosis of MI predicated on 0- and 2-h serial testing based on sex-specific 99th percentiles. Novel observations were observed for findings based on different URLs and for females and MI types.