Total Analytic Error for Low Cardiac Troponin Concentrations (a?¤10 ng/L) by Use of a High-Sensitivity Cardiac Troponin Assay

摘要

To the Editor: There are considerable data suggesting that low cardiac troponin (cTn)1 concentrations measurable only by high-sensitivity cTn (hs-cTn) assays can be used for medical decision-making (1). However, there are limited data on the long-term analytical performance of hs-cTn related to the bias and imprecision associated with cTn concentrations a?¤10 ng/L, which are not measurable with contemporary assays (2). For quality assurance purposes having a total analytic error (TAE) criterion at low concentrations would help identify problematic hs-cTn reagent/calibrator lots and suboptimal analyzer performance. This is a practical concern, as previous negative biases with the Roche hs-cTnT assay were identified and ultimately corrected by the manufacturer, but only after multiple different reagent lots were used clinically (3). Lot-to-lot or batch-to-batch evaluations for reagents and calibrators to identify minor shifts in hs-cTn results can be difficult, time-consuming, and expensive. The goal of this analysis was to establish a realistic TAE for cTnI concentrations a?¤10 ng/L measured by the Abbott assay by assessing concentration biases between different lots of reagents/calibrators and imprecision at low cTn concentrations. Our approach to evaluating new hs-cTn lots involved comparing approximately 10 samples (fresh, not frozen) with cTn concentrations that spanned the measuring range on both lots, ideally with 3 samples containing cTn a?¤10 ng/L (4). We pooled results from lot-to-lot comparisons over a 2-year period (2015a??2016), which allowed us to assess the long-term difference a?|