| A-a | alveolar-atrial |
|---|---|
| A-a O2 | alveolo-arterial oxygen tension |
| A-C | acromioclavicular; adult-versus-child; aortocoronary bypass |
| A-CAH | autoimmune chronic active hepatitis |
| A-COM | Anterior COMmunicating artery |
| A-EMT | advanced emergency medical technician |
| A-IC | average integrated concentration |
| A-LAK | adherent lymphokine-activated killer [cell] |
| A-M pr | Austin-Moore prosthesis |
| A-m2 | ampere-square meter |