The American Society of Anesthesiologists (ASA) physical status classification system

ASA 1
Normal healthy patient
ASA 2
Patient with mild controlled systemic disease which does not affect normal activity
ASA 3
Patient with severe systemic disease which limits activity
ASA 4
Patient with severe systemic disease which is incapacitating and is a constant threat to life
ASA 5
Moribund patient not expected to survive 24 hours with or without operation