| Abbreviation | Definition |
|---|---|
| HA | Heart Attack |
| HA | hemagglutinin |
| HA | High Anxiety |
| HA | Hospital Admission |
| HAA | Hepatitis Associated Antibodies |
| HAART | Highly Active Anti Retroviral Therapy |
| HABIT | Hips, Abdominals, Butts, and Incredible Thighs |
| HAC | HyperAdrenoCorticism |
| HACA | Human Anti-Chimeric Antibody |
| HAE | Hereditary AngioEdema |
| HAEC | Human Aortic Endothelial Cell |
| HAFE | High Altitude Flatus Expulsion |
| HAGMA | High Anion Gap Metabolic Acidosis |
| HAGS | Herpes, AIDS, Ghonorrea, Syphilis |
| HAI | Hospital Acquired Infection |
| HAL | Hand Assisted Laparoscopy |
| HAM | Health, Action, and Mind |
| HAM-D | Hamilton Depression Rating Scale |
| HAP | Human Anatomy and Physiology |
| HAPE | High Altitude Pulmonary Edema |