Written by Clay Smith
In this single center, the Generation 5 high-sensitivity troponin T assay would have allowed acute MI rule out at baseline in 29% of patients and 41% at 30 minutes with 100% NPV and sensitivity. This needs multicenter prospective confirmation, but it shows the future feasibility and utility of high sensitivity troponin pathways.
Why does this matter?
High sensitivity troponin assays have been used in Europe for quite some time but were only recently approved in the U.S. The question is how best to utilize these assays. This is one potential rapid rule-out protocol.
Will this get a REACTION?
This was a study of the diagnostic accuracy of the recently approved Generation 5 high sensitivity cardiac troponin t assay (hsTnT) in patients presenting to a single ED with possible acute coronary syndrome (ACS). They enrolled 569 patients, 7.7% of which were adjudicated to have acute MI. The hsTnT was drawn at baseline and 30 minutes. No patients with a baseline hsTnT of <6ng/L (164 patients – 28.8%) had MI; NPV and sensitivity 100%. No patients with initial hsTnT <8ng/L and Δ <3 ng/L at 30-minutes (221 patients – 41%) were diagnosed with MI; NPV and sensitivity 100%. The low end of the 95% confidence intervals for the NPVs were each about 98%. As a secondary outcome, 30-day major adverse coronary event (MACE) rate was also low – 1.2% in the baseline rule-out group and 0.5% using the baseline and 30-minute repeat TnT, but loss to follow up at 30-days was considerable.
Ultrarapid Rule-out for Acute Myocardial Infarction Using the Generation 5 Cardiac Troponin T Assay: Results From the REACTION-US Study. Ann Emerg Med. 2018 Dec;72(6):654-664. doi: 10.1016/j.annemergmed.2018.06.021. Epub 2018 Aug 14.
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