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Background: The Atellica® VTLi point-of-care (POC) High Sensitivity Cardiac Troponin-I (hs-cTnI) assay is intended for use as an aid in the diagnosis of myocardial infarction (MI). Our primary objective is to assess its diagnostic performance in patients presenting with suspected acute coronary syndrome (ACS)., Methods: This prospective observational study will enrol ∼1500 patients at ∼20 U.S. Emergency Departments. After informed consent, adults (>21 years of age) with suspected ACS, and no prior enrollment in this study, will provide a fingerstick and venous blood sample within 2 h of ED presentation, >2 to ≤4 h, and >4 to ≤9 h (max. blood draw = 60 mL). HEART and EDACS scores will be prospectively documented. Patients without the first blood draw may be enrolled if the second draw was obtained. Capillary and venous whole blood will undergo Atellica VTLi assay testing, with remaining venous sample processed to plasma and run. All results will be blinded to the clinical care team. Site operators will undergo a 3-day familiarization period. Quality control testing will be performed daily. At 30 ± 3 days, patient mortality status, major adverse cardiac events, and rehospitalizations will be determined. A clinical endpoint adjudication committee, blinded to hs-cTnI VTLi result, will define the final diagnosis. Sensitivity, specificity, and predictive values will describe the assay performance., Results: We expect study completion within 114 weeks of enrollment of the first patient., Conclusions: It is anticipated that the Atellica VTLi hs-cTnI assay validation study will define a performance equivalent to lab-based hs-cTnI, with results within ∼8 min at the point of care., Competing Interests: Declaration of Competing Interest This study was sponsored by Siemen's Healthineers. Each of the non-Siemen's employee author's institutions received financial support to enroll patients in this trial., (Copyright © 2023. Published by Elsevier Inc.)

Objectives: To compare emergency department TnI serial sampling intervals, determine optimal diagnostic thresholds, and report representative diagnostic performance characteristics for early rule-in and rule-out of MI., Methods: We prospectively measured TnI (AccuTnI+3™, Beckman Coulter) at serial time intervals in 1929 subjects with chest pain or equivalent ischemic symptoms suggestive of acute coronary syndromes at 14 medical centers. Diagnosis was adjudicated by an independent central committee., Results: TnI ≥0.03ng/mL provided 96.0% sensitivity and 89.4% specificity at 1-3h after admission, and 94.9% sensitivity and 86.7% specificity at 3-6h. NPV (rule-out, non-MI) was 99.5% at 1-3h, and 99.0% at 3-6h when TnI is <0.03ng/mL. NPV was 99.1% when TnI is <0.03ng/mL and time of symptom onset is ≥8h. Approximately 50-58% (PPV) of patients with TnI ≥0.03ng/mL were diagnosed with MI, depending upon time from onset or admission; PPVs emphasize the importance of serial samples and delta TnI (rising or falling pattern) when low cutoffs are used. Nevertheless, even a single elevated TnI value increased the risk of MI. As TnI values rose, the probability of MI increased. Values ≥0.20ng/mL were associated with nearly 90% probability of MI., Conclusions: We report a large multicenter prospective adjudicated trial assessing troponin for early rule-in and rule-out using the Universal Definition of MI and conducted in primary care hospital-associated emergency departments. Our study demonstrates high diagnostic accuracy at early observation times, and reinforces consensus recommendations for sampling on admission and 3h later, repeated at 6h when clinical suspicion remains high., (Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)

Objectives: We investigated absolute and relative cardiac troponin I (TnI) delta changes, optimal sampling protocols, and decision thresholds for early diagnosis of myocardial infarction (MI). Serial cardiac biomarker values demonstrating a rise and/or fall define MI diagnosis; however the magnitude of change, timing, and diagnostic accuracy of absolute versus relative (percentage) deltas remains unsettled., Methods: We prospectively measured TnI (AccuTnI+3™, Beckman Coulter) at serial time intervals in 1929 subjects with chest pain or equivalent symptoms of acute coronary syndrome at 14 medical centers. Diagnosis was adjudicated by an independent central committee., Results: Elevated TnI above a threshold of 0.03ng/mL demonstrated significant diagnostic efficacy (AUC 0.96). For patients with TnI<0.03ng/mL and symptom onset≥8h, 99.1% (NPV) were diagnosed with conditions other than MI. Absolute delta performed significantly better than relative delta at 1-3h (AUC 0.84 vs 0.69), 3-6h (0.85 vs 0.73), and 6-9h (0.91 vs 0.79). Current recommendations propose ≥20% delta within 3-6h; however, results were optimized using an absolute delta of 0.01 or 0.02ng/mL. Sensitivity results for absolute delta at 1-3h and 3-6h (75.8%, 78.3%) were superior to relative delta (48.0%, 61.3%). NPV (rule out) was 99.6% when baseline TnI<0.03ng/mL and absolute delta TnI<0.01ng/mL., Conclusions: Absolute delta performed significantly better than relative delta at all time intervals. Baseline TnI and absolute delta may be used in conjunction to estimate probability of MI. Consensus recommendations are supported for sampling on admission and 3h later, repeated at 6h in patients when clinical suspicion remains high., (Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)