This session will focus on the critical role of companion diagnostics (CDx) and theranostics in advancing personalized and precision medicine. Experts will discuss how predictive diagnostic tests are developed and validated to identify patients who are most likely to benefit from specific targeted therapies ? maximizing efficacy and minimizing adverse effects. The session will also cover theranostic approaches that combine targeted diagnostics and therapeutics in a single platform, especially in oncology, nuclear medicine, and emerging fields. Regulatory pathways, co-development strategies, and real-world clinical implementation challenges will be highlighted.