Early Rule Out With a Refreshed Troponin Assay

In 2008, Roche Diagnostics introduced a high-sensitivity version of their cardiac troponin T assay (hs-cTnT), a fifth-generation assay. Researchers quickly deduced that by using the assay’s limit of detection (LoD) of 5 ng/L (to convert to micrograms per liter, multiply by 0.001) as a cutoff, many patients could safely be classified as very low-risk for myocardial infarction (MI).

Researchers gathered data across multiple institutions, and a 9241-patient meta-analysis demonstrated a pooled sensitivity for the LoD of 98.7%. Outside the US, on presentation (0-hour) concentrations less than LoD became guideline recommended, reassuring patients quickly and reducing time spent in busy emergency departments (EDs).

Once US Food and Drug Administration (FDA) approval was obtained in the US, a similar risk-stratification approach became possible, though using a threshold of 6 ng/L because the FDA mandated that exact concentrations below the limit of quantitation (LoQ) be not reported. In the meantime, troponin I assay manufacturers brought to market high-sensitivity cardiac troponin I (hs-cTnI) assays.