Bernice Engeltjes,1,2 Corlijn Van Dijk,3 Ageeth Rosman,2 Rudy Rijke,2 Fedde Scheele,1,4 Eveline Wouters5 1Athena Institute for Transdisciplinary Research, Faculty of Science, VU University, Amsterdam, the Netherlands; 2Department of Healthcare Studies, Rotterdam University of Applied Sciences, Rotterdam, the Netherlands; 3Department of Obstetrics, University Medical Center Utrecht, Utrecht, the Netherlands; 4Department of Healthcare Education, OLVG Teaching Hospital, Amsterdam, the Netherlands; 5Department of Tranzo, Tilburg School of Social and Behavioral Sciences, Tilburg University, Tilburg, the NetherlandsCorrespondence: Bernice EngeltjesDepartment of Health Care Studies, Rotterdam University of Applied Sciences, Rochussenstraat 198, Rotterdam, 3015 EK, the NetherlandsTel +31 6 41804881Email engeltjesbernice@gmail.comObjective and Purpose: A triage system that prioritizes care according to medical urgency has a favorable effect on safety and efficiency of emergency care. The Dutch obstetric telephone triage system is comparable to physical triage systems. It consists of five urgency levels: resuscitation and life threatening (U1), emergency (U2), urgent (U3), non-urgent (U4) and self-care advice (U5). The purpose of this study was to determine the diagnostic and external validity of the Dutch obstetric telephone triage system in obstetric emergency care.Patients and Methods: The validity of the Dutch obstetric telephone triage system was studied in a prospective observational study in four hospitals. Diagnostic validity of usual care was determined by comparing the assigned urgency level of the Dutch obstetric telephone triage system with a reference standard. This reference standard was obtained by face-to-face clinical assessment in hospital following telephone triage. Clinical follow-up after assessment was also recorded. For statistical analyses, urgency levels were dichotomized into high urgency (U1, U2) and intermediate urgency (U3, U4). Self-care advice (U5) could not be studied because these patients ...