Objective: While existing research by our team has demonstrated the feasibility of building a decentralized identity management application ("MediLinker") for health information, there are implementation issues related to testing such blockchain-based health applications in real-world clinical settings. In this study, we identified clinical, organizational and regulatory, and ethical and social (CORES) issues, including recommendations, associated with deploying MediLinker, and blockchain in general, for clinical testing. Methods: CORES issues and recommendations were identified through a focus group with 11 academic, industry, and government experts on March 26, 2021. They were grouped according to their expertise: clinical care (n = 4), organizational and regulatory concerns (n = 4), and ethical and social issues (n = 3). The focus group was conducted via Zoom in which experts were briefed about the study aims, formed into breakout groups to identify key issues based on their group's expertise, and reconvened to share identified issues with other groups and to discuss potential recommendations to address such issues. The focus group was video recorded and transcribed. The resulting transcriptions and meeting notes were imported to MAXQDA 2018 for thematic analysis. Results: Clinical experts identified issues that concern the clinical system, clinical administrators, clinicians, and patients. Organizational and regulatory experts emphasized issues on accountability, compliance, and legal safeguards. Ethics and social-context experts raised issues on trust, transparency, digital divide, and health-related digital autonomy. Accordingly, experts proposed six recommendations that could address most of the identified issues: (1) design interfaces based on patient preferences, (2) ensure testing with diverse populations, (3) ensure compliance with existing policies, (4) present potential positive outcomes to top management, (5) maintain clinical workflow, and (6) increase the public's awareness of blockchain. Conclusions: This study identified a myriad of CORES issues associated with deploying MediLinker in clinical settings. Moreover, the study also uncovered several recommendations that could address such issues. The findings raise awareness on CORES issues that should be considered when designing, developing, and deploying blockchain for healthcare. Further, the findings provide additional insights into the development of Me-diLinker from a prototype to a minimum viable product for clinical testing. Future studies can use CORES as a socio-technical model to identify issues and recommendations associated with deploying health information technologies in clinical settings.