Analytical and clinical characterization of a novel high-sensitivity cardiac troponin assay in a United States population

• Published in: Clinical biochemistry Vol. 83; pp. 28 - 36
• Main Authors: Christenson, Robert H., Duh, Show-Hong, Mullins, Kristin E., LeClair, Margot M., Grigorov, Ilya L., Peacock, W. Frank
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.09.2020
• Subjects: Acute Coronary Syndrome - blood; Acute Coronary Syndrome - diagnosis; Adult; Aged; Aged, 80 and over; Female; Humans; Immunoassay - methods; Limit of Detection; Male; Middle Aged; Myocardial Infarction - blood; Myocardial Infarction - diagnosis; Reference Values; Sensitivity and Specificity; Sex Factors; Troponin I - blood; United States; United States
• ISSN: 0009-9120; 1873-2933; 1873-2933
• DOI: 10.1016/j.clinbiochem.2020.05.014

Cardiac troponin (cTn) is the keystone for diagnosis of acute myocardial infarction (AMI). We examined the analytical and clinical diagnostic characteristics of the ACCESS hsTnI assay in a United States (US) population. All measurements and studies were conducted using a lithium heparin matrix. Sex-specific 99th percentile upper reference limits (URLs) were determined for 1089 healthy women (54.6%) and men using non-parametric statistics. High-sensitivity (hs) performance was assessed to determine if the total CV was ≤10% at sex-specific URLs, and if ≥50% of cTnI values for each sex exceeded the assay’s limit of detection (LoD). Precision, analytical measurement range, high-dose hook effect, and endogenous/exogenous interferences were examined with CLSI guidance. Clinical characterization included serial sampling of 1854 suspected AMI subjects presenting to 14 US Emergency Departments. AMI was adjudicated by a panel of expert cardiologists. The study’s only exclusion was end stage renal disease. 99th percentile URLs were 11.6-, 19.8- and 17.5-ng/L for respective female, male and all-subject populations. Total %CV was <8% from 6.8 to 19,000 ng/L, and <6% at sex-specific 99th percentiles; ≥99% of ACCESS hsTnI values for each sex exceeded the LoD. No high-dose hook effect or endogenous/exogenous interferences were identified. A comparison of Baseline samples collected at ≤1 h and any-time after presentation, found 4% lower sensitivity for AMI than with earlier sampling. For 1–9 h post presentation, the sensitivity was >90%, specificity >85%; and negative and positive predictive value were ≥99% and >60%, respectively. Analytical and clinical performance of the ACCESS hsTnI assay meets the definition of a hs cTn method. The ACCESS hsTnI assay has good precision over a wide range, no significant interferences, and sensitivity >90% and NPV ≥99%. Performance is appropriate for aiding in AMI diagnosis.