Classification
ASA physical status
Also known as: ASA score, ASA classification, ASA-PS
The ASA physical status classification is a six-point scale published by the American Society of Anesthesiologists to describe a patient's systemic health before anaesthesia. ASA 1 is a normal healthy patient and ASA 6 is a declared brain-dead organ donor. It describes health, not surgical risk, and an "E" suffix marks emergency procedures.
- Published by
- American Society of Anesthesiologists
- Range
- ASA 1 to ASA 6
- Emergency suffix
- E — e.g. ASA 3E
- Describes
- Systemic health, not procedural risk
The six classes
| Class | Definition | Example |
|---|---|---|
| ASA 1 | Normal healthy patient | Non-smoker, minimal alcohol use |
| ASA 2 | Mild systemic disease, no functional limitation | Well-controlled hypertension, current smoker, BMI 30–40 |
| ASA 3 | Severe systemic disease, functional limitation | Poorly controlled diabetes, BMI over 40, ESRD on dialysis |
| ASA 4 | Severe systemic disease that is a constant threat to life | Recent MI or stroke, sepsis, severe valve dysfunction |
| ASA 5 | Moribund, not expected to survive without the operation | Ruptured abdominal aneurysm, massive trauma |
| ASA 6 | Declared brain-dead, organs being removed for donation | — |
A common misreading
ASA class is frequently used as shorthand for “how risky is this case”, which it is not. It describes the patient’s systemic health independent of the procedure. A healthy ASA 1 patient undergoing a high-risk operation and an ASA 3 patient having a cataract removed are not comparable on the basis of the class alone.
This matters operationally as well as clinically. A pre-admission clinic that triages by ASA class will fill with ASA 2 patients who need nothing, while the frail patient whose functional capacity is the actual concern gets a phone call. Triaging by screened risk rather than by classification is the difference Pathways is built around.