| ARPT | American Registry of Physical Therapists |
|---|---|
| ARR | aortic root replacement |
| arr | arrest, arrested |
| ARRC | Associate of the Royal Red Cross |
| ARRS | American Roentgen Ray Society |
| ARRT | American Registry of Radiologic Technologists |
| ARS | Anti-Rabies Serum |
| ARS | acquiescence response scale; adult Reye's syndrome; alcohol-related seizures; alizarin red S; American Radium Society; American Rhinologic Society; antirabies serum; arsphenamine; arylsulfatase; autonomously replicating sequence |
| Ars | arsphenamine |
| ARSA | American Reye's Syndrome Association; arylsulfatase A |