A High-Sensitivity Troponin I Rapid Assay vs. a High-Sensitivity Troponin T Routine Assay in Acute Chest Pain Patients: A Prospective Monocentric Study

<b>Background/Objective</b>: The measurement of troponin is recommended for acute myocardial infarction (AMI) diagnosis. Yet, hs-cardiac troponin T (hs-cTnT) can be elevated due to non-cardiac conditions, such as skeletal muscle injury, chronic kidney disease (CKD) or pulmonary embolism. The aim of our study was to compare the diagnostic accuracy of a bedside rapid hs-cardiac troponin I (hs-cTnI) assay (Quidel TriageTrue^®) with hs-cTnT measured in a routine laboratory (Roche Elecsys). <b>Methods</b>: This prospective monocentric study was conducted in an acute cardiac outpatient unit at a tertiary hospital. Hs-cTnI was measured via a point-of-care test from whole blood, while hs-cTnT was measured from plasma through the routine laboratory facility. <b>Results</b>: In 129 patients (65.1% male, 61.8 ± 15.6 years) with acute chest pain, results for hs-cTnI were available 14 ± 11 min after the first clinical presentation, which was 74 ± 54 min earlier than for hs-cTnT. Coronary angiography confirmed AMI in 17 patients (13.28%). The relative risk of AMI patients with elevated hs-cTnI results was 6.59 compared to 2.29 for hs-cTnT. Hs-cTnI exhibited an equivalent negative predictive value to hs-cTnT (99%) for AMI but had a comparatively higher positive predictive value (50.0 vs. 25.8%). In 39 patients with at least CKD stage 3a, median hs-cTnT was pathological (27.0 ng/L), in contrast with hs-cTnI (11.2 ng/L). Further, hs-cTnI was less likely elevated in patients with CKD and no AMI. <b>Conclusions</b>: The diagnostic value of hs-cTnI was comparable to that of hs-cTnT, and the blood sampling-to-result time was shorter than routine hs-cTnT.