| AAPM | American Association of Physicists in Medicine |
|---|---|
| AAPM&R | American Academy of Physical Medicine and Rehabilitation |
| AAPMC | antibiotic-associated pseudomembranous colitis |
| AaPO2, (A-a) PO2 | alveolo-arterial oxygen tension difference |
| AAPP | American Academy on Physician and Patient |
| AAPPO | American Association of Preferred Provider Organizations |
| AAPS | American Association of Plastic Surgeons; Arizona Articulation Proficiency Scale; Association of American Physicians and Surgeons |