| GUA | group of units of analysis |
|---|---|
| HAA | hearing aid amplifier; hemolytic anemia antigen; hepatitis-associated antigen; hospital activity ana... |
| HDA | heteroduplex analysis; Huntington Disease Association; hydroxydopamine |
| IAC | image analysis cytometry; ineffective airway clearance; internal auditory canal; interposed abdomina... |
| ICA | Institute of Clinical Analysis; internal carotid artery; intracranial aneurysm; islet cell antibody |