Modified Project Summary/Abstract Section Black adolescents and young adults (AYAs) are disproportionately affected by the HIV epidemic. In Alabama (AL), a state identified in the Ending the HIV Epidemic (EHE) initiative for America as a geographic hot spot, over 30% of new HIV infections occur in people aged 13 to 24 with over 80% of these infections occurring in Black AYAs. In addition to high HIV incidence rates among this population, sexually transmitted infection (STI) rates are also high in the South with Black AYAs disproportionately impacted. Given the largely asymptomatic nature of both HIV and STIs, testing is necessary for diagnoses; however, only 9% of adolescents have ever been tested for HIV and yearly STI testing rates for this population are around 9%. Utilizing a syndemic theory approach requires the consideration of other co-existing epidemics among this population, such as mental illness, drug usage, and the social determinants of health (SDH) and how they may synergistically increase HIV and STI acquisition risk. To improve HIV diagnosis in an EHE priority area we propose to evaluate various HIV and STI testing modalities (i.e., facility based versus at home testing). We will assess the feasibility, acceptability, and testing modality preferences for student populations at a Historically Black College and University (HBCU), Stillman College, in Tuscaloosa, AL. The RE-AIM and CFIR implementation science frameworks will be utilized in addition to a syndemics theory framework to better understand the role of syndemics in testing modality preferences and follow through. In Aim 1, we will collect process data from Five Spot, the HIV and STI testing provider and our community partner, to evaluate the uptake, distribution, and use of various STI and HIV testing modalities. Five Spot will offer HIV and STI testing options to students attending Stillman while collecting data on testing uptake and follow-up care (e.g., number of students tested, STI and HIV testing modality used, number of students testing positive for any STI and/or HIV, testing and/or treatment/linkage to care or prevention). In Aim 2, we will use a quantitative, online survey with 200 students attending Stillman College to assess preferences for STI and HIV testing modalities (i.e., facility-based versus at home testing, secondary distribution to partners), sexual risk behaviors, STI and HIV testing history, past medical history, implementation outcomes informed by RE-AIM, and syndemic factors that may impact testing uptake and testing preferences, such as mental illness, drug usage, and SDH. In Aim 3, if awarded year 2, we will conduct qualitative in-depth interviews with key stakeholders and students attending Stillman College to explore barriers and facilitators to uptake and/or follow through of HIV/STI testing and treatment and identify additional needed services. The stakeholder interviews will focus on sustainability, opportunities for expansion, and unmet ne...