Background: We demonstrate the performance of the bioMérieux VIDAS Troponin I Ultra assay for diagnostic accuracy for detection of myocardial infarction (MI) and risk stratification.
Method: cTnI was measured in 545 patients from 2 clinical centers with symptoms suggestive of ACS at admission, with an additional specimen at 4-12 h (453 patients). The 99th percentile value (0.01 microg/l) was used to assess clinical accuracy for diagnosis of acute MI. Primary endpoint for risk stratification was first of cardiac event or death in 302 patients (one center) followed for 60 days.
Results: 157 (28.8%) patients ruled in for an MI during index hospitalization. Sensitivities and specificities were 88.1% (95% CI 81.9 to 92.4%) and 79.9% (CI 75.5 to 83.6%) for baseline and 100% (CI 96.5 to 100%) and 79.4% (CI 74.4 to 83.4%) for follow-up specimens. ROC curve areas increased from 0.912 (CI 0.879 to 0.944) at baseline to 0.994 (CI 0.988 to 0.999) at second sampling (n=453, p<0.01); with no differences between sites. Primary endpoint rate for the 223 patients (74%) with normal cTnI on presentation was lower than the 79 patients (26%) with cTnI>0.01 ug/l (5.9% vs. 42.3%, p<0.0001). The relative risk for the >0.01 ug/l group was 8.9 (CI 4.6 to 17).
Conclusion: The VIDAS cTnI assay is a sensitive diagnostic method for the early detection of MI and predicts increased risk for adverse events in patients with symptoms suggestive of ACS.