ASA Physical Status Classification (ASA I–VI)
A scan-ready reference to ASA I–VI definitions, population-specific examples, the emergency E modifier, difficult boundaries, common errors, and final assignment.
Purpose and scope
ASA Physical Status (ASA-PS) assesses and communicates a patient’s pre-anaesthesia medical comorbidities.
Procedure type, frailty, deconditioning, urgency, and other perioperative factors are assessed separately; ASA-PS alone does not predict an individual patient’s perioperative risk.
Adult ASA I–VI classification
| ASA Class | Official definition | Selected adult examples |
|---|---|---|
| ASA I | ASA I: a normal healthy patient. | Healthy, nonsmoking, with no or minimal alcohol use. |
| ASA II | ASA II: a patient with mild systemic disease. | Mild disease without substantive functional limitation or end-organ involvement; current smoking, social alcohol use, obesity with 30 < BMI < 40, well-controlled diabetes or hypertension, and mild lung disease. |
| ASA III | ASA III: a patient with severe systemic disease. | Substantive functional limitation or one or more moderate-to-severe diseases; poorly controlled diabetes or hypertension, COPD, compensated cirrhosis, BMI ≥ 40, regularly dialysed end-stage renal disease, or history more than three months after myocardial infarction, cerebrovascular accident, transient ischaemic attack, or coronary artery disease/stent placement. |
| ASA IV | ASA IV: a patient with severe systemic disease that is a constant threat to life. | Recent events less than three months after myocardial infarction, cerebrovascular accident, transient ischaemic attack, or coronary artery disease/stent placement; ongoing cardiac ischaemia, severe valve disease, shock, sepsis, disseminated intravascular coagulation, acute respiratory distress syndrome, end-stage renal disease without regular dialysis, or uncompensated cirrhosis. |
| ASA V | ASA V: a moribund patient who is not expected to survive without the operation. | Ruptured abdominal or thoracic aneurysm, massive trauma, intracranial bleeding with mass effect, or ischaemic bowel with significant cardiac disease or multiple organ dysfunction. |
| ASA VI | ASA VI: a declared brain-dead patient whose organs are being removed for donor purposes. | No separate adult example is added beyond the definition. |
ASA I
- Official definition
- ASA I: a normal healthy patient.
- Selected adult examples
- Healthy, nonsmoking, with no or minimal alcohol use.
ASA II
- Official definition
- ASA II: a patient with mild systemic disease.
- Selected adult examples
- Mild disease without substantive functional limitation or end-organ involvement; current smoking, social alcohol use, obesity with 30 < BMI < 40, well-controlled diabetes or hypertension, and mild lung disease.
ASA III
- Official definition
- ASA III: a patient with severe systemic disease.
- Selected adult examples
- Substantive functional limitation or one or more moderate-to-severe diseases; poorly controlled diabetes or hypertension, COPD, compensated cirrhosis, BMI ≥ 40, regularly dialysed end-stage renal disease, or history more than three months after myocardial infarction, cerebrovascular accident, transient ischaemic attack, or coronary artery disease/stent placement.
ASA IV
- Official definition
- ASA IV: a patient with severe systemic disease that is a constant threat to life.
- Selected adult examples
- Recent events less than three months after myocardial infarction, cerebrovascular accident, transient ischaemic attack, or coronary artery disease/stent placement; ongoing cardiac ischaemia, severe valve disease, shock, sepsis, disseminated intravascular coagulation, acute respiratory distress syndrome, end-stage renal disease without regular dialysis, or uncompensated cirrhosis.
ASA V
- Official definition
- ASA V: a moribund patient who is not expected to survive without the operation.
- Selected adult examples
- Ruptured abdominal or thoracic aneurysm, massive trauma, intracranial bleeding with mass effect, or ischaemic bowel with significant cardiac disease or multiple organ dysfunction.
ASA VI
- Official definition
- ASA VI: a declared brain-dead patient whose organs are being removed for donor purposes.
- Selected adult examples
- No separate adult example is added beyond the definition.
Paediatric ASA I–VI examples
| ASA class | Official definition | Paediatric examples |
|---|---|---|
| ASA I | ASA I: a normal healthy patient. | Healthy, with no acute or chronic disease, and a normal BMI percentile for age. |
| ASA II | ASA II: a patient with mild systemic disease. | Asymptomatic congenital cardiac disease, well-controlled dysrhythmia, asthma without exacerbation, well-controlled epilepsy, non-insulin-dependent diabetes mellitus, abnormal BMI percentile for age, mild or moderate obstructive sleep apnoea, oncologic disease in remission, or autism with mild limitations. |
| ASA III | ASA III: a patient with severe systemic disease. | Uncorrected stable congenital cardiac abnormality, asthma with exacerbation, poorly controlled epilepsy, insulin-dependent diabetes mellitus, morbid obesity, malnutrition, severe obstructive sleep apnoea, active oncologic disease, renal failure, muscular dystrophy, cystic fibrosis, history of organ transplantation, brain or spinal cord malformation, symptomatic hydrocephalus, premature infant with post-conceptual age under 60 weeks, autism with severe limitations, metabolic disease, difficult airway, long-term parenteral nutrition, or a full-term infant under 6 weeks of age. |
| ASA IV | ASA IV: a patient with severe systemic disease that is a constant threat to life. | Symptomatic congenital cardiac abnormality, congestive heart failure, active sequelae of prematurity, acute hypoxic-ischaemic encephalopathy, shock, sepsis, disseminated intravascular coagulation, automatic implantable cardioverter-defibrillator, ventilator dependence, endocrinopathy, severe trauma, severe respiratory distress, or advanced oncologic disease. |
| ASA V | ASA V: a moribund patient who is not expected to survive without the operation. | Massive trauma, intracranial haemorrhage with mass effect, need for ECMO, respiratory failure or arrest, malignant hypertension, decompensated congestive heart failure, hepatic encephalopathy, ischaemic bowel, or multiple organ dysfunction. |
| ASA VI | ASA VI: a declared brain-dead patient whose organs are being removed for donor purposes. | The current statement lists no separate paediatric example for ASA VI. |
ASA I
- Official definition
- ASA I: a normal healthy patient.
- Paediatric examples
- Healthy, with no acute or chronic disease, and a normal BMI percentile for age.
ASA II
- Official definition
- ASA II: a patient with mild systemic disease.
- Paediatric examples
- Asymptomatic congenital cardiac disease, well-controlled dysrhythmia, asthma without exacerbation, well-controlled epilepsy, non-insulin-dependent diabetes mellitus, abnormal BMI percentile for age, mild or moderate obstructive sleep apnoea, oncologic disease in remission, or autism with mild limitations.
ASA III
- Official definition
- ASA III: a patient with severe systemic disease.
- Paediatric examples
- Uncorrected stable congenital cardiac abnormality, asthma with exacerbation, poorly controlled epilepsy, insulin-dependent diabetes mellitus, morbid obesity, malnutrition, severe obstructive sleep apnoea, active oncologic disease, renal failure, muscular dystrophy, cystic fibrosis, history of organ transplantation, brain or spinal cord malformation, symptomatic hydrocephalus, premature infant with post-conceptual age under 60 weeks, autism with severe limitations, metabolic disease, difficult airway, long-term parenteral nutrition, or a full-term infant under 6 weeks of age.
ASA IV
- Official definition
- ASA IV: a patient with severe systemic disease that is a constant threat to life.
- Paediatric examples
- Symptomatic congenital cardiac abnormality, congestive heart failure, active sequelae of prematurity, acute hypoxic-ischaemic encephalopathy, shock, sepsis, disseminated intravascular coagulation, automatic implantable cardioverter-defibrillator, ventilator dependence, endocrinopathy, severe trauma, severe respiratory distress, or advanced oncologic disease.
ASA V
- Official definition
- ASA V: a moribund patient who is not expected to survive without the operation.
- Paediatric examples
- Massive trauma, intracranial haemorrhage with mass effect, need for ECMO, respiratory failure or arrest, malignant hypertension, decompensated congestive heart failure, hepatic encephalopathy, ischaemic bowel, or multiple organ dysfunction.
ASA VI
- Official definition
- ASA VI: a declared brain-dead patient whose organs are being removed for donor purposes.
- Paediatric examples
- The current statement lists no separate paediatric example for ASA VI.
Obstetric examples
Although pregnancy is not a disease, uncomplicated pregnancy is ASA II because the parturient’s physiology is significantly altered from the non-pregnant state.
| ASA class | Obstetric examples |
|---|---|
| ASA II | Uncomplicated pregnancy, well-controlled gestational hypertension, or diet-controlled gestational diabetes. |
| ASA III | Preeclampsia with or without severe features, poorly controlled or complicated gestational diabetes or high insulin requirement, or thrombophilic disease requiring anticoagulation. |
| ASA IV | Preeclampsia with severe features complicated by HELLP or another adverse event, peripartum cardiomyopathy, or uncorrected or decompensated acquired or congenital heart disease. |
| ASA V | Uterine rupture or amniotic-fluid embolism. |
ASA II
- Obstetric examples
- Uncomplicated pregnancy, well-controlled gestational hypertension, or diet-controlled gestational diabetes.
ASA III
- Obstetric examples
- Preeclampsia with or without severe features, poorly controlled or complicated gestational diabetes or high insulin requirement, or thrombophilic disease requiring anticoagulation.
ASA IV
- Obstetric examples
- Preeclampsia with severe features complicated by HELLP or another adverse event, peripartum cardiomyopathy, or uncorrected or decompensated acquired or congenital heart disease.
ASA V
- Obstetric examples
- Uterine rupture or amniotic-fluid embolism.
Emergency E modifier
The E modifier denotes emergency surgery when delaying treatment would significantly increase the threat to life or a body part.
ASA IIIE shows the format. E does not change the underlying ASA class and is not a seventh severity category.
Assigning ASA-PS
Identify the patient’s systemic diseases and relevant physiologic state.
Assess disease control and severity, substantive functional limitation, and end-organ involvement.
Compare the findings with the current definition and the correct adult, paediatric, or obstetric example column.
Determine the E modifier separately from the underlying class.
Combine ASA-PS with procedure type, frailty, deconditioning, urgency, and other perioperative factors; the class alone does not determine monitoring, vascular access, vasopressor use, ICU admission, or postoperative destination.
Difficult boundaries
- Smoking and alcohol
Current smoking or social alcohol use appears among adult ASA II examples; no or minimal alcohol use and nonsmoking appear under ASA I.
- Obesity and BMI
For adults, 30 < BMI < 40 appears under ASA II and BMI ≥ 40 under ASA III. Paediatric assignment uses the BMI percentile for age rather than adult BMI boundaries.
- Disease control
Distinguish well-controlled mild disease from poorly controlled or complicated disease; use the complete definition and the population-specific examples.
- Function and end-organ involvement
Substantive functional limitation and end-organ involvement help separate mild from severe disease. Reduced ejection fraction is qualitative in the current statement; do not add a numeric cutoff.
- Cardiovascular event timing
For the listed adult myocardial, cerebral, or coronary events, history more than three months appears under ASA III and an event less than three months under ASA IV.
- Infection and sepsis
A local infection without systemic signs does not by itself reproduce the adult ASA IV examples; sepsis and shock do. Classify the patient’s systemic state, not the procedure label.
- Pregnancy
Uncomplicated pregnancy is ASA II because physiology is significantly altered, although pregnancy is not a disease. Complications are matched to the obstetric examples.
- Prematurity and young infants
The ASA III paediatric examples include a premature infant with post-conceptual age under 60 weeks and a full-term infant under 6 weeks of age.
- Oncologic state
The paediatric examples distinguish oncologic disease in remission, active oncologic disease, and advanced oncologic disease; do not classify from the word cancer alone.
- Brain death and organ donation
ASA VI is reserved for a patient with declared brain death whose organs are being removed for donor purposes.
Common misinterpretations
Procedure magnitude and urgency do not themselves determine the numeric ASA class; the E modifier records emergency status separately.
E is a modifier, not a seventh severity class.
Age alone is not an additional class. Use the applicable adult or paediatric definition and examples.
The current statement uses qualitative moderate and severe reduction of ejection fraction; it does not supply a numeric cutoff.
In one single-centre cohort of adults undergoing elective non-cardiac surgery, ASA-PS assignment had moderate inter-rater reliability; this finding does not establish class cutoffs and does not extend to paediatric or obstetric assignment.
Sources
1. Primary source
American Society of Anesthesiologists Statement on ASA Physical Status Classification System
American Society of Anesthesiologists · Anesthesiology Open 2026;1(1):e0002; April 2026
Accessed Jul 29, 2026
2. Supporting source
Reliability of the American Society of Anesthesiologists physical status scale in clinical practice
Sankar et al. · British Journal of Anaesthesia 2014;113(3):424–432
Accessed Jul 29, 2026