| Abbreviation | Definition |
|---|---|
| CIO | Chief Information Officer |
| CIO | Congress of Industrial Organizations |
| CIR | Committee of Interns and Residents |
| CIS | Care Information System |
| CIS | Catheter-Induced Spasm |
| CIS | Central Issue System |
| CIS | Coronary Intervention Study |
| CISA | Clinical Immunization Safety Assessment |
| CISO | Clinical Investigations Support Office |
| CITIS | Computed Industrial Tomographic Imaging System |
| CJTS | Centrul Judetean de Transfuzie Sanguina |
| CK | Centesimal Korsakovian |
| CKD-EPI | Chronic Kidney Disease - Improved Prediction Equations |
| CLAS | Center for Learning Arthroscopic Skills |
| CLASP | Cholesterol Lowering Agent to Slow Progression |
| CLE | Complete Local Excision |
| CLI | Common Language Infrastructure |
| CLIP | Children's Longterm Inpatient Program |
| CLLIQ | Clear Liquids |
| CLMR | Clinical Leadership and Management Review |