ASA Physical Status Classification System: the six classes (and the E) a dentist writes on the sedation consent

What it says#

The classification is one table. The ADA's Guidelines for the Use of Sedation and General Anesthesia by Dentists, adopted by the ADA House of Delegates in October 2025, reprint it under the heading American Society of Anesthesiologists (ASA) Patient Physical Status Classification, excerpted from the ASA's Statement on ASA Physical Status Classification System, 2020, and that reprint is where the definitions and examples below are read from. ASA I: a normal healthy patient; adult examples, healthy, non-smoking, no or minimal alcohol use. ASA II: a patient with mild systemic disease; mild diseases only without substantive functional limitations, such as a current smoker, social alcohol drinker, pregnancy, obesity with a BMI between 30 and 40, well-controlled diabetes or hypertension, mild lung disease. ASA III: a patient with severe systemic disease; substantive functional limitations, one or more moderate to severe diseases, such as poorly controlled diabetes or hypertension, COPD, morbid obesity with a BMI of 40 or more, active hepatitis, alcohol dependence or abuse, an implanted pacemaker, moderate reduction of ejection fraction, end-stage renal disease undergoing regularly scheduled dialysis, a premature infant with a postconceptional age under 60 weeks, or a history more than 3 months old of MI, CVA, TIA or coronary artery disease with stents. ASA IV: a patient with severe systemic disease that is a constant threat to life; a recent MI, CVA, TIA or CAD with stents within 3 months, ongoing cardiac ischemia or severe valve dysfunction, severe reduction of ejection fraction, sepsis, DIC, ARD, or end-stage renal disease not undergoing regularly scheduled dialysis. ASA V: a moribund patient who is not expected to survive without the operation; a ruptured abdominal or thoracic aneurysm, massive trauma, intracranial bleed with mass effect, ischemic bowel in the face of significant cardiac pathology or multiple organ or system dysfunction. ASA VI: a declared brain-dead patient whose organs are being removed for donor purposes. The addition of E denotes emergency surgery, an emergency being defined as existing when delay in treatment of the patient would lead to a significant increase in the threat to life or body part.

The ASA's own description of the system, on its physical status modifiers page, is that it is used to assess and communicate a patient's pre-anesthesia medical co-morbidities; that the status of patients undergoing surgery under anesthesia ranges from a healthy patient to one who is critically ill or injured; that a patient with a past or current disease or condition may require different anesthesia care than a healthier patient undergoing the same procedure; and that the assignment of a physical status classification is a clinical determination made by the anesthesiologist after evaluating the patient. The same page shows what the class means in anesthesia payment: physical status modifiers add nothing for ASA I and II, one additional base unit for ASA III and two for ASA IV in its example vignettes, and the ASA supports their use by Medicare and private insurers.

The dental use is the ADA's. Its 2025 guidelines say that for minimal sedation, healthy or medically stable individuals (ASA I, II) should have a review of their current medical history and medication use, and patients with significant medical considerations (ASA III, IV) may require consultation with their primary care physician or consulting medical specialist; for moderate sedation, patients with significant medical considerations (e.g., ASA III, IV) should also require that consultation; and for deep sedation or general anesthesia, they must have it. The AAE's Endodontic Case Difficulty Assessment Form uses the same scale as its first criterion: no medical problem (ASA class 1 or 2) is low difficulty, one or more medical problem (ASA class 3) is moderate, and a complex medical history, serious illness or disability (ASA class 4) is high.

A caution about this entry. The ASA's statement page on asahq.org and the Anesthesiology Open article it now links to both refused automated access in this session, so the class definitions and adult examples are reported here exactly as the ADA reprints them from the 2020 version, and the statement's pediatric and obstetric examples and its approval and amendment history are not reported. If your protocol needs those, open the ASA article in a browser.

Who it applies to#

Any patient about to receive anesthesia or sedation, which in a dental office means every patient on the schedule for nitrous oxide, oral or IV sedation, or general anesthesia, and in practice every patient whose medical history is being updated. The class is assigned by the clinician who evaluates the patient; in the hospital that is the anesthesiologist, and under the ADA guidelines it is the dentist or the anesthesia provider working under state rules. The ADA guidelines also ask for a BMI as part of the pre-procedural workup, which is why the BMI thresholds in the ASA II and III examples matter at the front desk.

It is not a procedure risk estimate and not a rule about which patients may be treated. The ASA says its payment vignettes should not be used to determine a real patient's status, and the ADA's rules turn on the class only to decide who needs a physician's consultation before sedation, alongside the ASA's separate fasting recommendations and its continuum-of-sedation definitions, which the ADA reprints next to the table.

What changed#

The scale is old and the wording has moved. The AAE's case difficulty form carries, in a footnote, an earlier five-class version: class 1 no systemic illness, class 2 mild systemic illness without functional restrictions, class 3 severe illness that limits activities but does not immobilize, class 4 severe illness that immobilizes and is sometimes life threatening, class 5 not expected to survive 24 hours, with a link to an asahq.org address that no longer resolves. The version the ADA reprints as 2020 has six classes, defines ASA IV by a constant threat to life rather than immobilization, and adds the adult examples with their numbers: BMI 30 to 40 for class II and 40 or more for class III, the 3-month line for MI, CVA, TIA and stents between classes III and IV, and scheduled versus unscheduled dialysis.

The most recent change is where the statement lives. The ASA's Standards and Practice Parameters index now links the Statement on ASA Physical Status Classification System to a DOI in Anesthesiology Open, the ASA's open journal, where the Crossref record shows it published on December 12, 2025 as volume 1, issue 1, article e0002 under a CC BY-NC-ND license. The ADA's October 2025 guidelines cite the 2020 statement; whether the journal version changed the examples could not be verified here.

Where the source is#

The link under the title is the DOI the ASA's Standards and Practice Parameters index uses for the statement, which resolves to the Anesthesiology Open article on the publisher's site (Wolters Kluwer); the ASA's older statement page at asahq.org/standards-and-practice-parameters/statement-on-asa-physical-status-classification-system and the journal page both answered automated requests with a JavaScript challenge in this session, so the statement was not read directly. The class definitions and adult examples above are from the ADA Guidelines for the Use of Sedation and General Anesthesia by Dentists (October 2025, free PDF on ada.org), which reprint the ASA's 2020 statement; the ASA's description of the system is from its Physical Status Modifier Payments page, updated May 28, 2026; and the publication details are from the Crossref record for the DOI.