| IID | Interaural intensity difference |
|---|---|
| IIEF | International Index of Erectile Function |
| IIF | Indirect Immunofluorescence test |
| IIF | Indirect immunofluorescence |
| IIF | Indirect immunofluorescent |
| IIF | Intracellular Ice Formation |
| IIF | indirect immunofluorescence assay |
| IIF | indirect immunofluorescence technique |
| IIFT | indirect Immunofluorescence test |
| IIH | Idiopathic Intracranial Hypertension |