Objectives:Due to the persistent primary care physicians shortage and the substantial increase in their workload, the organization of primary care calls during out-of-hours periods has become an everyday challenge. The SALOMON algorithm is an original nurse telephone triage tool allowing to dispatch patients to the best level of care according to their conditions. This study evaluated its reliability and criterion validity in rea-life settings. Methods:In this 5-year study, out-of-hours primary care calls were dispatched into four categories: Emergency Medical Services Intervention (EMSI), Emergency Department referred Consultation (EDRC), Primary Care Physician Home visit (PCPH), and Primary Care Physician Delayed visit (PCPD). We included data of patients' triage category, resources, and destination. Patients included into the primary care cohort were classified undertriaged if they had to be redirected to an emergency department (ED). Patients from the ED cohort were considered overtriaged if they did not require at least three diagnostic resources, one emergency-specific treatment or any hospitalization. In the ED cohort, only patients from the University Hospitals were considered. Results:10,207 calls were triaged using the SALOMON tool: 19.2% were classified as EMSI, 15.8% as EDRC, 62.8% as PCPH, and 2.2% as PCPD. The triage was appropriate for 85.5% of the calls with a 14.5% overtriage rate. In the PCPD/PCPH cohort, 96.9% of the calls were accurately triaged and 3.1% were undertriaged. SALOMON sensitivity and specificity reached 76.6% and 98.3%, respectively. Conclusion:SALOMON algorithm is a valid triage tool that has the potential to improve the organization of out-of-hours primary care work.