A slightly updated ASA score
And would having an ASA 3.5 category add more clarity?
The American Society of Anesthesiologists (ASA) physical classification system aims to categorize patients based on disease status with numbers ranging from 1 to 6.
ASA 1 is a healthy person.
ASA 2 has mild systemic disease.
ASA 3 has severe systemic disease.
ASA 4 has disease that is a constant threat to life.
ASA 5 is someone who is not expected to survive without the proposed surgery.
ASA 6 is a brain-dead patient whose organs are being donated.
In January 2026, the ASA updated their table of examples for the ASA physical status classification system. One change that caught my eye was the classification of obstructive sleep apnea (OSA). Mild and moderate OSA count as an ASA 2 if a patient is using continuous positive airway pressure (CPAP), but count as an ASA 3 if the patient is not using CPAP. Severe OSA falls under ASA 3 regardless of CPAP use. Here are the other new examples for adults:
ASA 2: CHF NYHA class 1, mild cognitive dysfunction
ASA 3: CHF NYHA classes 2 and 3, significant cognitive dysfunction,1 poorly controlled diabetes mellitus or hypertension with or without end-organ dysfunction
ASA 4: CHF NYHA class 4, uncompensated cirrhosis, severe cognitive dysfunction
For pediatrics, having a risk of malignant hyperthermia (e.g. family history) is now an ASA 2.
For pregnant patients, preeclampsia without severe features is now classified as an ASA 3 instead of an ASA 2. For ASA 5, amniotic fluid embolism was added to the examples.
I wish they had added concrete values to descriptions such as “poorly controlled diabetes mellitus” and “uncompensated cirrhosis.” What hemoglobin A1c or MELD score constitutes those descriptions? And where does an overweight but otherwise healthy adult fit? A pediatric patient with an “abnormal BMI” would be at least an ASA 2, but why do the adult examples fail to comment on the BMI range of 25–29.9?
Why ASA 3 lacks clarity
People who fall into categories 1, 2, 4, and 5 are pretty clear. Where I find the system fails to give meaningful stratification between patients is in the ASA 3 category. Take, for example, the following two patients.
Person one is a male with mild OSA who is not using CPAP. Based on the new examples, this patient is an ASA 3 due to noncompliance with CPAP. If he used CPAP, then he would be an ASA 2.
Person two is a female with hypertension, coronary artery disease (CAD) with two stents (placed more than 3 months ago), diabetes with a hemoglobin A1c of 9.8%, daily acid reflux symptoms, an occasional smoking habit, stage 3 chronic kidney disease, hepatic steatosis, and a BMI of 45. This person is also an ASA 3, yet is far sicker than person one.
Having such a broad range of patients in the ASA 3 category decreases its usefulness in understanding patient comorbidities. For this reason, I don’t put a lot of stock into the ASA status unless it is a 1, 4, or 5. But what if there could be more granularity by breaking down an ASA 3 into ASA 3.0 and ASA 3.5?
I would propose that if a patient has certain diseases, such as CAD, a prior stroke, or chronic obstructive pulmonary disease (COPD), they are automatically an ASA 3.5. Additionally, if a patient has five or more severe diseases (I have no evidence-based reason for choosing the number five), that also bumps them up to an ASA 3.5. In this way, a clearer separation between patients could make the ASA 3 classification more useful.
What do you think about this idea? How much attention do you pay to the ASA score?
Do they mean moderate cognitive impairment? The Clinical Dementia Rating (CDR) and the Global Deterioration Scale (GDS) do not list “significant” as a specific category.