Analytical Performance Evaluated for Troponin T Gen 5 Assay

Increased blood concentrations of cardiac troponin (cTn) I and T are indicative of myocardial injury and are the preferred biomarkers for diagnosing acute myocardial infarction (AMI). The diagnosis of AMI requires a rise and/or fall in serial cTn measurements, in addition to other clinical features.

The introduction of high-sensitivity assays has enabled the rapid detection of subtle changes in cTn and facilitated earlier decision-making in the management of patients with suspected AMI, compared with less sensitive contemporary assays. These newer assays which can measure cTn concentrations 5 to 10 times lower than current assays and do so with improved analytical imprecision.

A team of Medical Scientists collaborating with the University of California San Diego Health (San Diego, CA, USA) analyzed the performance of the Elecsys Troponin T Gen 5 STAT assay. This assay is an electrochemiluminescence sandwich immunoassay, which uses two antibodies to form a sandwich complex with cTnT. A biotinylated monoclonal anti-cTnT-specific antibody and a monoclonal anti-cTnT-specific antibody labeled with ruthenium react to form a sandwich complex. Precision was evaluated per Clinical and Laboratory Standards Institute (CLSI) EP05-A2 using lithium-heparin plasma/quality control samples on Roche cobas e 411/cobas e 601 analyzers.

The scientists reported that the coefficients of variation (CV) for repeatability/intermediate precision were 0.7–5.6%/1.4–10.3% (cobas e 411; mean cardiac troponin T [cTnT]: 7.3–9,341 ng/L) and 0.7–3.0%/1.5–6.4% (cobas e 601; mean cTnT: 7.4–9,455 ng/L). There was no cross-reactivity with skeletal muscle troponin T (≤ 10,000 ng/L), skeletal muscle troponin I (≤ 100,000 ng/L), cardiac troponin I (≤ 10,000 ng/L), or human troponin C (≤ 80,000 ng/L). No interference was observed with biotin (≤ 20 ng/mL) or 34 drugs. The specified limit of blank and limit of detection were 3 ng/L and 5 ng/L, respectively, on the cobas e 411 analyzer, and 2.5 ng/L and 3 ng/L, respectively, on the cobas e 601 analyzer.

The authors concluded that the Elecsys TnT Gen 5 STAT assay demonstrated good analytical performance on cobas e 411 and cobas e 601 analyzers, with a CV of ≤ 10% at the 99th percentile URL. These findings support the routine use of the assay in clinical laboratories in the USA. The study was published in the August 2019 issue of the journal Clinica Chimica Acta.

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