The Medical Dictionary for Regulatory Activities: the global standard terminology used to code adverse events and medical conditions in clinical trials.
Maintained by the International Council for Harmonisation (ICH), MedDRA is structured across five hierarchical levels: System Organ Class (SOC), High-Level Group Term (HLGT), High-Level Term (HLT), Preferred Term (PT), and Lowest Level Term (LLT).
Unlike healthcare billing codes (ICD-10-CM or CPT) which focus on claim reimbursement, MedDRA standardizes clinical safety data for regulatory reporting to the FDA, EMA, and PMDA across multi-center trials.