Evaluating Tiered Hemolysis Thresholds to Facilitate Rapid Reporting of High-Sensitivity Cardiac Troponin

Abstract

Abstract Background Cardiac troponin (cTn) assays are used for the diagnosis of acute myocardial infarction and frequently require serial measurements. Recollection of unacceptable specimens for hemolysis can delay results and disrupt timing of serial measurements. This study was designed to assess the influence of hemolysis on a high-sensitivity cTnT assay in granular detail at clinically important concentrations. These were used in consultation with the clinical practice to evaluate risk-based thresholds for acceptable amounts of hemolysis. Methods Plasma pools ranging from <10 to >100 ng/L cTnT were spiked with hemolysate to various degrees of hemolysis and measured using the Elecsys Troponin T Gen 5 STAT assay. The impact of accepting expanded hemolysis thresholds was completed using retrospective data of 12225 serial cTnT results and an additional 4651 baseline cTnT results. Results The mean percent change in cTnT was consistent for a given degree of hemolysis regardless of the initial nonhemolyzed cTnT concentration. Tiered hemolysis thresholds were evaluated for low-risk patients (apparent cTnT ≤8 ng/L), intermediate-risk patients (thresholds for 9–37 ng/L, 38–66 ng/L, and 67–99 ng/L cTnT), and high-risk patients (≥100 ng/L cTnT). The influence of tiered hemolysis thresholds was calculated for patients with serial (0 and 2 h) cTnT results, which demonstrated that the majority of 2-h delta interpretations were unchanged. Implementation of tiered thresholds dramatically decreased recollections for hemolyzed cTnT samples. Conclusion Tiered hemolysis cutoffs minimized disruption to patient care for low- and high-risk patients, while maintaining the integrity of serial measurements for those with intermediate cTnT concentrations.