| AAA |
abdominal aortic aneurysm |
| A-a |
gradient alveolar to arterial gradient |
| AAD |
antibiotic-associated diarrhea |
| AAO |
alert, awake, and oriented |
| A&O |
alert & oriented |
| AAS |
acute abdominal series |
| ABD |
abdomen |
| ABG |
arterial blood gas |
| AC |
before eating |
| ACLS |
advanced cardiac life support |
| ACTH |
adrenocorticotropic hormone |
| ADH |
anti-diuretic hormone |
| ADR |
adverse drug reaction OR acute dystonic reaction |
| ad lib |
as much as needed |
| AED |
antiepileptic drug |
| AF |
atrial fibrillation OR afebrile |
| AFB |
acid-fast bacilli |
| AFP |
alpha-fetoprotein |
| A /G |
albumin/globulin ratio |
| AI |
aortic insufficiency |
| AIDS |
Acquired Immune Deficiency Syndrome or acquired immunodeficiency syndrome |
| AKA |
above the knee amputation |
| ALD |
alcoholic liver disease |
| ALL |
acute lymphocytic leukemia |
| amb |
ambulate |
| AML |
acute myelogenous leukemia |
| ANA |
antinuclear antibody |
| ANS |
autonomic nervous system |
| AOB |
alcohol on breath |
| AODM |
adult onset diabetes mellitus |
| AP |
anteroposterior OR abdominal - perineal |
| ARDS |
acute respiratory distress syndrome |
| ARF |
acute renal failure |
| AS |
aortic stenosis |
| ASAP |
as soon as possible |
| ASCVD |
atherosclerotic cardiovascular disease |
| ASD |
atrial septal defect |
| ASHD |
atherosclerotic heart disease |
| AV |
atrioventricular |
| A-V |
arteriovenous |
| A-VO2 |
arteriovenous oxygen |
