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The FDA cleared the first in a new generation of cardiac troponin T (TnT) blood tests for rapid diagnosis of acute MI, Roche's Elecsys TnT Gen 5 STAT test, .
The company's blood test uses two monoclonal antibodies against cardiac troponin T to pick up the marker of myocardial damage with a turn-around time of 9 minutes.
Such TnT blood tests have been used in Europe and other regions for 7 years, Roche noted. European labels note less than 10% coefficient of variation at the 99th percentile upper reference limit of 14 ng/L and a limit of detection of 5 ng/L.
However, Roche is not yet releasing such details for the U.S. label, pending FDA release of its summary, a public relations spokesperson said.
Moreover, the company is not allowed to call it a “high-sensitivity†troponin T test, advised by the FDA to use the term “next generation†instead, although it is the same test referred to as a high-sensitivity TnT assay in published studies and outside the U.S., she said.
Still, Roche's announcement touted advantages over standard assays for faster decision making and detection of smaller infarcts. It quoted emergency physician Frank Peacock MD, of Baylor Medical Center Houston, as saying, "FDA clearance of this new Roche TnT assay is easily the best news in the last decade for emergency medicine patients presenting with chest pain."
However, one sticking point has been the exact cutoffs and management protocols to use for these assays. One trial from Australia showed no impact of reporting levels with the more sensitive test in the absence of explicit protocols, except for patients with levels below 30 ng/L.
"Adoption of high-sensitivity troponin testing is likely to require coupling with management protocols that guide interpretation and care if the benefits of greater diagnostic discrimination are to be harnessed," the study researchers had concluded.
The FDA clearance was based in part on a study of more than 1,000 patients with suspected acute MI in more than a dozen U.S. centers, although again the details were not released.