Objective: To assess the validity of the Manchester Triage System (MTS) in paediatric emergency care, using information on vital signs, resource utilisation and hospitalisation. Methods: Patients were eligible if they had attended the emergency department of a large inner-city hospital in The Netherlands from August 2003 to November 2004 and were ,16 years of age. A representative sample of 1065 patients was drawn from 18 469 eligible patients. The originally assigned MTS urgency levels were compared with resource utilisation, hospitalisation and a predefined reference classification for true urgency, based on vital signs, resource utilisation and follow-up. Sensitivity, specificity and percentage of overtriage and undertriage of the MTS were calculated. Results: The number of patients who used more than two resources increased with a higher level of MTS urgency. The percentage of hospital admissions increased with the increase in level of urgency, from 1% in the non-urgent patients to 54% in emergent patients. According to the reference classification, the sensitivity of the MTS to detect emergent/very urgent cases was 63%, and the specificity was 78%. Undertriage occurred in 15% of patients, of which 96% were by one urgency category lower than the reference classification. Overtriage occurred in 40%, mostly in lower MTS categories. In 36% of these cases, the MTS classified two or more urgency categories higher than the reference classification. Conclusions: The MTS has moderate sensitivity and specificity in paediatric emergency care. Specific modifications of the MTS should be considered in paediatric emergency care to reduce overtriage, while maintaining sensitivity in the highest urgency categories.H ospital emergency departments are increasingly visited by patients with non-urgent problems.1-3 This leads to overcrowded waiting rooms and long waiting times. As a consequence, patients needing care urgently may not be treated in time, whereas patients with non-urgent problems may unnecessarily receive expensive emergency care. Therefore, a reliable, valid triage system is required for patient safety. Triage of paediatric patients is difficult as presenting signs and symptoms and final diagnoses differ from those of adults.4 Several triage systems have been developed to categorise patients by urgency of care.5-12 The Manchester Triage System (MTS), used by emergency department nurses, is a triage system that supports the determination of a patient's urgency level on the basis of discriminators embedded in problem-specific flow charts.
13The triage nurse selects the most suitable flow chart for each presenting problem and uses general and specific discriminators to identify the patient's acuity. The MTS provides clarity about maximum allowed waiting time for the different levels of urgency: ''emergent'' (red) needs instantaneous evaluation, ''very urgent'' (orange) needs evaluation within 10 min, ''urgent'' (yellow) within 60 min, ''standard'' (green) within 120 min and ''non-urgent'' (blue) can wait for up to ...