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Original research
Pre-hospital One-Hour Troponin in a Low-Prevalence Population of Acute Coronary Syndrome: OUT-ACS study
  1. Tonje R Johannessen1,2,
  2. Odd Martin Vallersnes1,2,
  3. Sigrun Halvorsen3,4,
  4. Anne Cecilie K. Larstorp4,5,
  5. Ibrahimu Mdala1 and
  6. Dan Atar3,4
  1. 1Department of General Practice, Institute of Health and Society, University of Oslo, Oslo, Norway
  2. 2Oslo Accident and Emergency Outpatient Clinic, City of Oslo Health Services, Oslo, Norway
  3. 3Department of Cardiology, Oslo University Hospital Ullevaal, Oslo, Norway
  4. 4Institute of Clinical Medicine, University of Oslo, Oslo, Norway
  5. 5Department of Medical Biochemistry, Section of Cardiovascular and Renal Reseach, Oslo University Hospital Ullevaal, Oslo, Norway
  1. Correspondence to Dr Tonje R Johannessen; t.r.johannessen{at}


Objective The European Society of Cardiology 0/1-hour algorithm for high-sensitivity cardiac troponin T (hs-cTnT) has demonstrated high rule-out safety in large hospital validation cohorts. We aimed to validate the algorithm in a primary care setting, where patients have a lower pretest probability for acute coronary syndrome.

Methods This prospective, observational, diagnostic study included patients with acute non-specific chest pain admitted to a primary care emergency clinic in Oslo, Norway, from November 2016 to October 2018. hs-cTnT was measured after 0, 1 and 4 hours. The primary outcome measure was the diagnostic performance of the 0/1-hour algorithm, the 90-day incidence of AMI or all-cause death the secondary.

Results Among 1711 included patients, 61 (3.6%) were diagnosed with AMI. By applying the algorithm, 1311 (76.6%) patients were assigned to the rule-out group. The negative predictive value was 99.9% (95% CI 99.5% to 100.0%), the sensitivity and specificity 98.4% (91.2–100.0) and 79.4% (77.4–81.3), respectively. Sixty-six (3.9%) patients were triaged towards rule-in, where 45 were diagnosed with AMI. The corresponding positive predictive value was 68.2% (58.3–76.7), sensitivity 73.8% (60.9–84.2), and specificity 98.7% (98.1–99.2). Among 334 (19.5%) patients assigned to the observation group in need of further tests, 15 patients had an AMI. The following 90 days, five new patients experienced an AMI and nine patients died, with a low incidence in the rule-out group (0.3%).

Conclusion The 0/1-hour algorithm for hs-cTnT seems safe, efficient and applicable for an accelerated assessment of patients with non-specific chest pain in a primary care emergency setting.

Trial registration number NCT02983123.

  • myocardial ischaemia and infarction (IHD)
  • acute coronary syndrome
  • cardiovascular examination
  • general practice
  • primary care

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  • Contributors All authors have contributed in the conception, drafting and revision of the article, and approved the final version for publication.

  • Funding TRJ received funding from the Norwegian Research Fund for General Practice, the Norwegian Committee on Research in General Practice and the Norwegian Medical Association's Fund for Quality Improvement and Patient Safety. The funders of the study had no role in study design, data collection, data analysis, data interpretation or writing of the report.

  • Competing interests DA has received speaker’s honoraria and consultancy fees from Amgen, Astra Zeneca, Bayer Healthcare, BMS, Boehringer-Ingelheim, Merck, Novartis, Pfizer and Sanofi-Aventis, and research grants from the institution by Medtronic and BMS. SH has received speaker’s honoraria and consultancy fees from Amgen, Astra Zeneca, Bayer Healthcare, BMS, Boehringer-Ingelheim, Merck, Novartis, Pfizer and Sanofi-Aventis, and has no conflicts in relation to this study.

  • Patient consent for publication Not required.

  • Ethics approval Written informed consent was obtained from all participants. The study was carried out according to the principles of the Declaration of Helsinki and was approved by the local ethics committees (Regional Committee North for Medical and Health Research Ethics (number 2016/1241) and the Oslo University Hospital Information Security and Privacy Office (number 2016/13308)).

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data availability statement Data may be made available upon reasonable request.

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