Clinical performance of a sixth-generation high-sensitivity cardiac troponin T assay compared with standard high-sensitivity troponin T in a real-world cohort

Background Advances in high-sensitivity cardiac troponin T (hs-cTnT) assay technology have improved the accuracy of detecting and quantifying cardiomyocyte injury in patients with suspected acute coronary syndrome (ACS). However, hs-cTnT concentrations may still be influenced by confounding factors unrelated to myocardial infarction. The novel sixth-generation high-sensitivity troponin T assay (hs-TnT-Gen6) offers enhanced analytical sensitivity and improved tolerance to haemolysis. Purpose To evaluate the diagnostic performance and reclassification safety of the hs-cTnT Gen 6 assay in a prospective, unselected real-world cohort. Methods We conducted a prospective observational study including 423 consecutive patients presenting to the emergency department (ED) of a tertiary university hospital in whom current standard hs-cTnT levels were measured. For each patient, a parallel blinded measurement using a hs-cTnT-Gen6 assay was performed in the hospital’s central laboratory. Categorical classification (low vs. high) was defined using a pre-specified threshold of 13 ng/L for standard hs-cTnT and the sex-specific 99th percentile upper reference limits for the Gen6 assay (18 ng/L for females; 32 ng/L for males). All patients were followed until discharge, and final diagnoses were adjudicated. Results Baseline characteristics of the study population (n = 423; median age 65.0 years [50.0–79.5]; 58.9% male), stratified according to sex-specific 99th percentile thresholds, are summarised in Table 1. A strong correlation was observed between the standard hs-cTnT and hs-cTnT-Gen6 assays (r = 0.98; p < 0.001). Bland–Altman analysis showed minimal differences within the normal range (≤13 ng/L), with deviations generally within ±5 ng/L. Above the 99th percentile, the absolute difference increased with concentration; at 200–400 ng/L, hs-cTnT Gen 6 values exceeded standard hs-cTnT by approximately 180–260 ng/L. Compared with the standard assay, hs-cTnT-Gen 6 reclassified 44 of 423 patients (10.4%): 43 cases (10.2%) were reclassified as normal, whereas only one (0.2%) was reclassified as high (Figure 1). Among the 43 downwardly reclassified patients, who represented 21% of initial high values with standard hs-cTnT, ACS was ruled out in 41 cases (95%), whereas the remaining two patients presented early with ST-segment elevation myocardial infarction and non-ST-segment elevation myocardial infarction, respectively. The single upwardly reclassified patient had not a final diagnosis of ACS. The categorical Net Reclassification Improvement was −9.9% (95% CI −12.9% to −7.0%). Conclusion The hs-cTnT Gen 6 assay may improve the precision of troponin-based risk stratification in the emergency department. In particular, it accurately reclassified a substantial proportion of low-risk individuals, which may contribute to more efficient resource utilisation.