Influence of Imprecision on ROC Curve Analysis for Cardiac Markers

Background: There has been considerable debate regarding the impact of assay imprecision on the performance of cardiac biomarkers for diagnosis of acute coronary syndromes (ACS) and risk stratification for future adverse cardiac events. Methods: Using existing data from 2 published clinical trials, we used a resampling method to statistically introduce 5%, 10%, and 20% imprecision to results for B-type natriuretic peptide (BNP) and cardiac troponin I (cTnI) and examined its impact on ROC curve analysis. Results: Superimposition of artificial imprecision produced no significant difference in the area under the ROC curve observed for BNP for diagnosis of heart failure or for cTnI for 30-day risk stratification of patients with ACS. Conclusion: Assay imprecision does not appear to be a critical determinant in the interpretation of cardiac marker results for patients with heart disease.