PROJECT SUMMARY/ABSTRACT In the United States, adolescents are the age group least likely to be aware of their HIV infection and linked to care in a timely manner, contributing to disproportionately low rates of viral suppression and increased risk of transmitting HIV to others. HIV testing is a cornerstone to HIV prevention, but uptake among adolescents is lagging. Adolescents who receive confidential care (i.e., have time alone with a health care provider during visits, the ability to self-consent to services, and the privacy of their health information maintained) are significantly more likely to engage in important discussions about sexual health issues, disclose sensitive sexual health information, receive appropriate sexual health services (e.g., HIV testing), and return for care. However, despite guidelines from professional medical organizations recommending universal access to confidential sexual health services, it is estimated that less than half of adolescents – the majority of whom are served in pediatric primary care settings – receive confidential care. Structural interventions targeting aspects of the environment that serve as barriers to HIV prevention offer an opportunity to increase adolescent HIV testing uptake by addressing the shortcomings of the systems in which sexual health services are delivered. This research will consider the perspectives of pediatric primary care patients, providers, and clinic leadership to develop a multicomponent structural intervention to increase adolescent HIV testing uptake by improving the implementation of confidential care as standard practice in pediatric primary care settings. This study will draw from the principles of community- based participatory research (CBPR) and utilize a multiphase optimization strategy to achieve the following specific aims: (1) explore patient preferences about how confidential care is provided in pediatric primary care; (2) examine provider- and organizational-level barriers and facilitators to implementing confidential care as standard practice in pediatric primary care; and (3) pilot test the feasibility and acceptability of structural intervention components to increase adolescent HIV testing uptake by improving the implementation of confidential care as standard practice in pediatric primary care. Consistent with the NIMH strategic plan goal to “strive for prevention and cures” by “optimizing the effectiveness of interventions for delivery in practice settings,” this Mentored Research Scientist Development Award (K01) will lay the groundwork for addressing health inequities among adolescents through structural interventions with high capacity for real-world implementation and dissemination. Through a combination of mentorship from a multidisciplinary team of experts at Yale University, coursework/workshops, experiential learning through the proposed research, and professional development activities, this K01 will provide Dr. Aivadyan with essential training...