Background: The PhenX (Phenotypes and eXposures) Toolkit (https://www.phenxtoolkit.org) is a web-based catalog of recommended measurement protocols and associated bioinformatics tools to assist with study design and facilitate cross-study data integration and analyses. The PhenX Toolkit currently includes measurement protocols from 29 research domains (e.g., Rare Genetic Conditions) and six collections that add depth to the Toolkit (e.g., Blood Sciences Research) and has over 4,200 registered users. Although an established resource that continues to expand content for investigators, the PhenX Toolkit does not currently contain measurement protocols specific to Sickle Cell Disease (SCD) Psychosocial or Social Determinants of Health (SDoH) outcomes. These outcomes were identified as key indicators by the National Academies of Sciences, Engineering and Medicine 2020 Report "Addressing Sickle Cell Disease: A Strategic Plan and Blueprint for Action.” This effort is supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH) through co-funding to the "PhenX Toolkit-Expansion and Sustainability” project award. Methods: PhenX protocols are recommended by domain experts using a consensus-based process that includes scientific community input. To identify protocols for the new collection, the PhenX SCD Research and Scientific Panel (SRSP) provided a list of scope elements for consideration and selected investigators with relevant expertise in psychology, behavioral science, hematology, and nursing to form a Psychosocial and SDoH Working Group (WG). A modified Delphi process was used to develop consensus on the topics and protocols. A set of 18 scope elements was initially developed and distributed to the WG (round 1). In round 2, preliminary consensus was reached on 12 topics via a virtual WG meeting. In round 3, WG members virtually presented background and recommendations for measurement protocols for the 12 topics and discussed these and other related protocols already included in the PhenX Toolkit. Consensus was reached on 12 primary protocols to move to the next phase, community outreach. Preliminary protocols will be shared with the scientific community for a 2-week period in which the community will have the opportunity to review and comment on the proposed protocols. The Psychosocial and SDoH WG will consider the outreach feedback in selecting final protocols to include in the SCD Research Collections. Results: The 12 measurement protocols recommended to-date include transition readiness (e.g., Sickle Cell Transition Intervention Program - Readiness for Transition (TIP-RFT)), self-management, impact of early aging (e.g., reactions to loss), stigma, trust in medical care and research, resilience, spirituality, and responses to stress. Some measures include multiple versions (e.g., parent/caregiver, child, adolescent, adult). Another 7 protocols were suggested as appropriate for supplemental information for this collection (e.g., American Society of Hematology Sickle Cell Disease Transition Readiness Assessment). Conclusion: This presentation will review the outreach data and the final recommendations of the WG and SRSP. These additional protocols will enhance the existing SCD Research Collections and the individual and structural SDoH protocols in the PhenX Toolkit. Furthermore, these recommendations will promote the use of valid and reliable measurement tools to investigate psychosocial constructs and social determinants of health in SCD. Funding was provided by a Genomic Research Grant (U41HG007050) from NHGRI, with current or prior funding support from the National Institute on Drug Abuse (NIDA); Office of Behavioral and Social Sciences Research (OBSSR); National Institute of Mental Health (NIMH); National Heart, Lung, and Blood Institute (NHLBI); National Institute on Minority Health and Health Disparities (NIMHD); and Tobacco Regulatory Science Program (TRSP).