| Abbreviation | Definition |
|---|---|
| IR | ionising radiation |
| IRB | Information Reader Box |
| IRP | idiopathic recurrent pancreatitis |
| IRP | Independent Reconfiguration Panel |
| IRP | independent review panel |
| IRP | insulin-releasing polypeptide |
| IRP | interstitial radiation pneumonitis |
| IRP | intramural research programme |
| IRP | isovolumic relaxation period |
| ISB | Information Standards Board |
| ISB | inner spiral bundle |
| ISB | Intercollegiate Specialty Examinations Board |
| ISB | International Society of Biomechanics |
| ISB | interscalene block |
| ISB | Invest to Save Budget |
| ISBHaSC | Information Standards Board for Health and Social Care |
| ISCM | IT Service Continuity Management |
| ISIP | Integrated Service Improvement Programme |
| ISMF | Information Security Management Forum |
| IT | iliotibial |