What is the ASA Physical Status classification?

The ASA PS system is a six-level scale used by anesthesiologists to describe a patient's overall health before surgery. Class I is a completely healthy patient; Class VI is a brain-dead patient being maintained for organ donation. An "E" suffix (e.g., ASA IIIE) is added for emergency procedures.

Does a higher ASA class mean surgery should be avoided?

No. The ASA class describes health status, not a contraindication to surgery. It informs risk discussions, guides pre-operative optimization, and helps plan anesthetic technique. The treating team weighs the surgical benefit against the estimated risk.

What is the difference between ASA III and ASA IV?

ASA III indicates a severe systemic disease with substantive functional limitations that is not an immediate constant threat to life (e.g., poorly controlled diabetes, stable COPD, ESRD on dialysis). ASA IV indicates a severe systemic disease that is a constant threat to life (e.g., recent MI within 3 months, severe heart failure with EF < 25%).

Is this classification validated for mortality prediction?

The ASA PS class correlates broadly with peri-operative mortality in population studies. ASA I carries an estimated 30-day mortality near 0.1%, while ASA IV approaches 7-8% in some series. However, it was not designed as a precise mortality calculator and should be combined with other risk tools (e.g., RCRI) for detailed counseling.

Who assigns the ASA class in practice?

The ASA class is assigned by the anesthesia provider (anesthesiologist or CRNA) during the pre-anesthetic evaluation. It is documented in the anesthesia record and may influence scheduling, monitoring level, and post-operative disposition.

ASA Physical Status Classifier

Select patient conditions to determine the ASA Physical Status class (I through VI) used to assess pre-operative anesthetic risk.

ASA Physical Status Class

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Select conditions on the left

Description

No conditions selected. Check one or more conditions to classify the patient.

Clinical Examples

Quick Reference

Class	Definition	Est. Mortality
I	Healthy patient	< 0.1%
II	Mild systemic disease	0.2%
III	Severe, not life-threatening	1.8%
IV	Constant threat to life	7–8%
V	Moribund, not expected to survive	~ 34%
VI	Brain-dead organ donor	N/A

Mortality estimates are population-level approximations from published literature. Individual risk depends on many additional factors. This tool is for educational reference only — always exercise clinical judgment.

Summary

The ASA Physical Status (PS) classification system is a standardized scale developed by the American Society of Anesthesiologists to assess a patient's pre-operative health status. It ranges from ASA I (healthy patient) through ASA VI (brain-dead organ donor). Clinicians use it to estimate anesthetic risk, guide pre-operative workup decisions, and communicate patient acuity across care teams.

How it works

Review the list of patient conditions across the six ASA classes (I–VI).
Check all conditions that apply to the patient.
The tool instantly calculates the highest applicable ASA class.
Read the class description, associated examples, and mortality estimate.
Use the result to guide pre-operative planning and documentation.
Click "Reset" to start a new assessment.

Use cases

Pre-operative anesthetic risk stratification before elective or emergency surgery.
Clinical documentation and anesthesia consent discussions.
Medical education and exam preparation for USMLE, NCLEX, and anesthesia boards.
Quick bedside reference for residents and anesthesiology students.
Triage support when evaluating urgency of operative scheduling.

ASA Physical Status Classifier

Patient Conditions

Summary

How it works

Use cases

Frequently Asked Questions

ASA Physical Status Classifier

Use the ASA Physical Status Classifier

Patient Conditions

Summary

How it works

Use cases

Frequently Asked Questions