BackgroundAlmost 80% of adolescents in the US have experienced a traumatic event, and approximately 7% have post-traumatic stress disorder. However, there is a lack of validated and feasible assessments for assessing traumatic stress symptoms in pediatric primary care, and traumatic stress symptoms are routinely unidentified. This study aimed to develop, pilot test, and assess the psychometric properties of the Adolescent Primary Care Traumatic Stress Screen (APCTSS), a five-item yes/no screener for post-traumatic stress symptoms in adolescents designed for use in pediatric primary care.MethodsThe APCTSS was developed by pediatricians, psychiatrists, psychologists, and social workers who all provide care to trauma-affected adolescent patients. The providers sought to create a developmentally appropriate tool that accurately reflected DSM-5 posttraumatic stress symptoms and that was feasible and acceptable for use in pediatric primary care. To develop the APCTSS, they combined and adapted the UCLA Post-traumatic Stress Disorder (PTSD) Reaction Index for DSM-5 with the adult Primary Care PTSD Screen for DSM-5. Next, 213 adolescent medicine patients were universally approached during routine clinic visits and 178 agreed to participate and were enrolled. The 178 patients were aged 13-22 (M=18.4, SD=2.3), 64.4% female; 62.1% Black or African-American, and 20.7% Hispanic/Latinx. Patients completed APCTSS, Patient Health Questionnaire for Adolescents (PHQ-A), and the Child PTSD Symptom Scale for DSM-5 Interview (CPSS-5-I), and 61 completed the Traumatic Events Screening Inventory for Children (TESI-C).Results56.7% reported a criterion A trauma, 30.1% met criteria for DSM-5 PTSD, 7.4% met criteria for subsyndromal PTSD symptoms, and 19.0% for post-event impairing symptoms. Validity and reliability testing indicated that the APCTSS was internally consistent, had good concurrent and discriminant validity, and demonstrated good sensitivity and specificity in identifying adolescents at high risk for post-trauma symptoms. Over half of patients (56.0%) who screened positive on the APCTSS (score ≥2) would not have been identified as having a mental health concern using the PHQ-A, including 60.8% of patients who had probable PTSD, subsyndromal PTSD, or post-event impairing symptoms.ConclusionsMany youth with trauma-related mental health symptoms are unidentified in pediatric primary care, which is a missed opportunity for early identification and may contribute to a host of poor outcomes. The development of an effective and feasible traumatic stress screening tool for youth primary care may improve early intervention, and the health and well-being of trauma affected youth.