Why is single sample rule out of non-ST elevation myocardial infarction using high-sensitivity cardiac troponin T safe when analytical imprecision is so high? A joint statistical and clinical demonstration.

This article examines the use of high-sensitivity cardiac troponin (hs-cTn) assays to rule out non-ST elevation myocardial infarction (NSTEMI). Despite concerns about assay imprecision, studies have shown that the single sample rule out (SSRO) method is safe. The article provides data on the imprecision of hs-cTnT assays and calculates the probability of misclassification for different troponin values. The risk of misclassification is low, particularly when the initial troponin value exceeds 7 ng/L. An alternative SSRO threshold of 6 ng/L has also been found to be clinically safe. The article also discusses the misclassification issue with the Roche elecys e801 hs-cTnT assay, which had a low rate of misclassification, with less than 0.08% of results in the range of 6-7 ng/L being misclassified. The study concludes that despite the imprecision, the assay is precise enough to ensure that misclassifications are rarely clinically significant. [Extracted from the article]