| MAR | main admissions room; marasmus; marrow; maximal aggregation ratio; medication administration record;... |
|---|---|
| MCA | major coronary artery; Maternity Center Association; medical care administration; methylcholanthrene... |
| MGA | master of general administration |
| MSA | major serologic antigen; male-specific antigen; mannitol salt agar; Medical Services Administration;... |
| MSHA | mannose-sensitive hemagglutination; Mine Safety and Health Administration |