High-Sensitivity Troponin Highlights the Need for New Methods to Evaluate Diagnostic Tests
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See Article by Adamson et al.
To be clinically useful, diagnostic tests need high precision. The original troponin assays had poor precision: they had high variability, particularly at the level used to determine whether a myocardial infarction (MI) was present.1 To address this problem, high-sensitivity troponin (hs Tn) assays were developed, the sensitivity referring not to the tests’ diagnostic sensitivity, but the analytic sensitivity with lower limits of detection and greater precision, including at the upper reference limit used to determine the presence of MI. This makes hs Tn more useful for ruling out MI and acute coronary syndrome in patients presenting with acute chest pain, allowing a greater proportion of patients to be discharged home earlier and potentially reducing the sex bias in the diagnosis of MI. These assays have been in use in Europe and Australasia since about 2010 but have only recently been approved by the Food and Drug Administration for clinical use in the United States.2
The study by Adamson et al3 in this issue of Circulation: Cardiovascular Quality and Outcomes demonstrates that hs Tn can also help determine which patients in a rapid access chest pain clinic are likely to have obstructive coronary artery disease. This is a well-conducted substudy of a larger trial although 50 of the 987 participants were excluded from the analysis: 44 did not have a troponin level and in 6 the coronary computed tomographic angiogram was not diagnostic, which may overestimate the diagnostic accuracy a little. Using the coronary computed tomographic angiogram as the reference standard, adding troponin to a validated risk score, the coronary artery disease Consortium risk model,4 modestly improved the diagnostic accuracy (C-statistic increased by 0.012 from 0.788 to 0.800; P=0.004) and the calibration of the model. Because the risk model includes …