BACKGROUND: High-sensitivity troponin assays (hs-Tn) detect lower serum concentrations than prior-generation assays and help guide acute coronary syndrome (ACS) evaluation in emergency departments. Outpatient hs-Tn utilization is not well described. HYPOTHESIS: Outpatient providers use hs-TnT to triage patients with suspected ACS. METHODS: We compared the volume of outpatient prior-generation troponin tests in the pre-hsTn implementation period (January 2015-March 2018) with outpatient hs-TnT volume in the post-implementation period (April 2018-January 2020). Triage patterns were compared between patients with hs-TnT>/=99th vs <99th percentile, using two-sample t tests. In patients triaged home, adverse events were compared between patients with hs-TnT>/=99th vs <99th percentile, using log-rank tests. RESULTS: Across a large tertiary healthcare system, a mean of 80 prior-generation tests/month were ordered during the pre-hsTn implementation period compared with 12 hs-TnT tests/month in the post-implementation period. Prior-generation orders rose by 1.72 tests/month during pre-implementation, vs a decline of 2.74 hs-TnT tests/month during post-implementation (P < .001). Among 129 hs-TnT orders, most were placed by cardiologists (54%) and primary care providers (32%). Patient symptoms at the time of troponin ordering included dyspnea (34%) and chest pain (33%), although 25% were asymptomatic. Among symptomatic patients (n = 74), those with hs-TnT > 99th percentile were more likely to be sent to the ED (RR, 3.36; 95% CI, 1.22-9.25; P = .002). Among patients sent home (n = 66), those with hs-TnT > 99th percentile had more adverse events by 6 months (3.3% vs 22.2% RR, 6.67; 95% CI, 1.04-42.9; P = .026). CONCLUSIONS: In this healthcare system, outpatient troponin utilization significantly declined since hs-TnT implementation. Some providers use hs-TnT to triage patients with suspected ACS to the ED; others test asymptomatic patients and some send patients home despite high hs-TnT values.