A-025 Clinical Performance Evaluation of a Novel Point-of-Care High Sensitivity Troponin I (i-STAT® hs-TnI) Cartridge with the i-STAT 1 System

Abstract Background Cardiac troponin is the gold-standard biomarker for detection of myocardial infarction (MI). High sensitivity cardiac troponin (hs-cTn) assays facilitate reliable measurement of low troponin concentrations and detection of small serial changes with higher precision than contemporary assays. However, most hs-cTn methods to date have been limited to large footprint, automated laboratory systems with long turnaround times. Availability of an accurate point-of-care method for hs-cTn measurement is of value given the urgency for timely MI diagnosis. This study aimed to evaluate the clinical performance of a novel point-of-care cardiac troponin I assay, the i-STAT High Sensitivity Troponin I (i-STAT hs-TnI) cartridge with the i-STAT System in whole blood. Methods A prospective cohort study of patients presenting to emergency departments (ED) with symptoms suggestive of acute coronary syndrome was conducted across 28 sites. ED sites were geographically diverse, representing regional, urban, and rural areas of the United States and ranged from small acute care hospitals to large tertiary care centers. Serial research specimens, when available, were collected from participants at 0–1 h, >1–3 h, >3–6 h, and >6 h from ED presentation and tested using the i-STAT hs-TnI assay. The primary outcome was index-visit MI, which was adjudicated by an independent panel of cardiologists and emergency physicians using each patient’s clinical presentation, medical history, and available clinical data, including the standard of care cardiac troponin level. Sensitivity, specificity, and positive and negative predictive values for MI were calculated based on the 99th percentile upper reference limit (URL) for apparently healthy individuals. Performance estimates and one-sided 97.5% lower confidence limits (LCL) were calculated according to guidelines in CLSI EP12. Acceptance criteria were applied to sensitivity and specificity. Error rates were also analyzed for i-STAT hs-TnI cartridge testing. Results A total of 3585 patients were included, of which 64% (2295/3585) were female with a median age of 59 years and 36% (1290/3585) were male with a median age of 60 years. MI occurred in 6.8% of females and 11.6% of males. Diagnostic performance estimates of the i-STAT hs-TnI assay in whole blood (using the overall 99th percentile URL of 21 ng/L) are presented with one-sided 97.5% LCL in Table 1. One-sided 97.5% LCLs for sensitivity and specificity met prespecified acceptance criteria. Of the 7489 cartridges tested, 129 quality check codes (QCC) and 11 star-outs were observed, for an error rate of 1.72% and 0.15% for QCCs and star-outs, respectively. The observed error rate for two consecutive cartridges due to QCCs was 0.11%.” Conclusion This study represents the largest clinical trial for a point-of-care high sensitivity cardiac troponin assay to date. The i-STAT hs TnI cartridge with the i-STAT 1 System recently cleared by the US Food and Drug Administration has high sensitivity and NPV comparable to core laboratory platforms. The assay’s fast turnaround time of ∼15 mins at the patient bedside, compared to ∼1 h for most laboratory hs-cTn platforms, will help facilitate implementation of rapid triage algorithms, offering major benefits to both patients and health care systems.