Background Chest pain is a common reason for contacting the emergency medical services (EMS). Troponins is a corner stone in ruling out high-risk conditions at the emergency department (ED) and the interest in using Troponins in the EMS setting is increasing. European Society of Cardiology (ESC) advocate the use of the 0/1 algorithm which allows rule-out after one Troponin test. However, no study has been validating the ESC 0/1 algorithm in the EMS setting.

Methods Observational cohort study including all patients with chest pain cared for by the EMS in the county of Halland, Sweden, during 2018. A blood sample was collected during the EMS mission and brought to the ED, where a high-sensitive Troponin T (hs-TnT) was analysed. The diagnosis at hospital discharge were retrieved from the hospital medical record. In total 2 917 EMS missions were included, of which 1 501 had an EMS hs-TnT test result. The sensitivity, specificity, negative and positive predictive value (NPV, PPV) of the ESC 0/1 algorithm’s ability to identify acute myocardial infarction (AMI) and other high-risk diagnoses were calculated. Applying only a hs-TnT result of <5 ng/L as rule-out cut-off.

Results For AMI identification the sensitivity was 99.4 (CI 95% 96.8-100.0), specificity 18.0 (CI 95% 19.9-20.1), PPV 13.4 (CI 95% 11.6-15.4) and NPV 99.6 (CI 95% 97.7-). Giving a rule-out rate of 16%, with <0.1% patients with AMI wrongly ruled-out.

For high-risk conditions (AMI, pulmonary embolism, aortic dissection etc.) identification the sensitivity was 98.4 (CI 95% 96.1-99.6), specificity 19.0 (CI 95% 16.1-19.1), PPV 20.0 (CI 95% 19.5-20.5) and NPV 98.3 (CI 95% 95.7-99.4), with four false negatives. Giving a rule-out rate of 16%, with <0.2% patients with high-risk conditions wrongly ruled out.

Conclusion By introducing high-sensitivity Troponins and applying the ESC 0/1 algorithm the EMS setting, high-risk conditions and especially AMI can be ruled out with high accuracy.