Key result
Point-of-care 0/2-hour hs-cTnI algorithm yields ~99% negative predictive value for index MI.
Why the study?
A 0/2-h algorithm for the i-STAT POC hs-cTnI assay was recently derived in Australia, motivating validation and optimization in a multisite U.S. ED cohort.
Does a 0/2-hour point-of-care high sensitivity troponin algorithm accurately diagnose or rule out index myocardial infarction in adults presenting to the emergency department without STEMI?
Cohort (n=578)
Yes
Does a 0/2-hour point-of-care high sensitivity troponin algorithm accurately diagnose or rule out index myocardial infarction in adults presenting to the emergency department without STEMI?
Effect estimate: NPV 99.4% (95% CI 97.7%-99.9%)
A 0/2-hour point-of-care high-sensitivity troponin algorithm demonstrates high negative predictive value and efficacy for ruling out myocardial infarction in the emergency department, potentially accelerating triage.
Original and optimized 0/2-h POC hs-cTnI algorithms achieved high NPV in US EDs; leaves open need for prospective trials before adoption.
OBJECTIVES: A 0/2-h algorithm for the i-STAT point-of-care (POC) high sensitivity troponin I (hs-cTnI) assay was recently derived in Australia. The objective of this study was to validate and optimize the performance of the 0/2-h algorithm in a multisite U.S. Emergency Department (ED) cohort. METHODS: A prospective cohort study was conducted at three U.S. EDs (February-September 2025). Adults without STEMI and at least one hs-cTnI ordered were accrued. Blood samples were collected simultaneously for POC hs-cTnI measurement on an i-STAT 1 analyzer (Abbott Laboratories) and central laboratory hs-cTnI measurement (Beckman Coulter). The primary outcome was index myocardial infarction (MI), adjudicated by experts using clinical hs-cTnI measures. Diagnostic performance of the Australian 0/2-h algorithm was assessed by calculating negative and positive predictive values (NPV, PPV) with associated 95% confidence intervals. Efficacy, defined as the proportion of patients classified into the rule-out zone, was calculated. Algorithm optimization tested modified cut points to increase efficacy while maintaining NPV ≥ 99% and achieving PPV ≥ 65%. RESULTS: During the study period, 578 patients with complete 0/2-h algorithm assessments were accrued. These patients were 48% (279/578) female, 40% (233/578) non-White, with a median age of 60 years (IQR: 50-70). Index MI occurred in 7.4% (43/578). Algorithm efficacy was 54.8% (317/578) and 8.8% (51/578) were classified to the rule-in zone. Among patients ruled-out, the NPV was 99.4% (95% CI: 97.7%-99.9%). The rule-in zone was associated with a PPV of 62.7% (95% CI: 48.1%-75.9%). Among 36.3% (210/578) patients classified to the observation zone, 4.3% (9/210) had an adjudicated index MI. An optimized 0/2-h algorithm increased efficacy to 60.0% (347/578) while achieving an NPV of 99.4% (95% CI: 97.9%-99.9%) and PPV of 74.4% (95% CI: 58.8, 86.5%) for index MI. CONCLUSIONS: The original Australian and optimized 0/2-h algorithms for i-STAT POC hs-cTnI measurement had high NPV and efficacy in a multisite U.S. TRIAL REGISTRATION: Trial Registration: NCT06899776.
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Mahler et al. (2026) conducted a cohort in Suspected myocardial infarction (n=578). 0/2-hour algorithm for i-STAT point-of-care high sensitivity troponin I was evaluated on Index myocardial infarction (MI) (NPV 99.4%, 95% CI 97.7%-99.9%). The 0/2-hour algorithm for i-STAT point-of-care high-sensitivity troponin I measurement achieved a negative predictive value of 99.4% (95% CI 97.7%-99.9%) for index myocardial infarction.
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