| Abbreviation | Definition |
|---|---|
| RDI | Reference Daily Intake |
| rDNA | Recombinant DeoxyriboNucleic Acid |
| RDRC | Radioactive Drug Research Committee |
| RDT | rising dose tolerance |
| RDT | Rising Drug Tolerance |
| RDTS | Reproductive and Developmental Toxicology Subcommittee |
| REDS-II | Retrovirus Epidemiology Donor Study Two |
| REE | Research, Education, and Economics |
| REG | Drug REGistration number |
| regneg | regulatory negotiation |
| ReGo | Reinventing the United States Government |
| REIS | Regional Economic Information System |
| REMS | Risk Evaluation and Mitigation Strategy |
| REMS: | Risk Evaluation and Mitigation Strategies |
| RES | Recall Enterprise System |
| RES | Recall Enterprise System (ORA) |
| RES | RESidence |
| RES(OC) | Regulations Editorial Section (OC) |
| RESNA | Rehabilitation Engineering & Assistive Technology Society of North America |
| RFA | Request For Application |