ASA I
Patients are considered to be healthy, non-smoking, with no or minimal alcohol use with the correct BMI for age. All major organs and organ systems appear in good health. Patients are able to walk up one flight of stairs or two level city blocks without distress. Little or no anxiety. Little or no risk during dental treatment. This classification represents a "green flag" for all dental treatment, usually not needing a medical consult unless other flags go up about patient hiding medical concerns when presented with an unhealthy general physical assessment.
ASA II
Patients have mild to moderate systemic disease or are healthy ASA I patients who demonstrate a more extreme anxiety and fear toward dentistry. Patients are able to walk up one flight of stairs or two level city blocks, but will have to stop after completion of the exercise because of distress since they do not have substantive functional limitations. Minimal risk during dental treatment. This classification represents a "yellow flag" for treatment, with a slight t warning flag indicating to proceed with caution with all dental care. Examples: History of well-controlled disease states including non-insulin dependent diabetes, prehypertension, epilepsy, asthma, or thyroid conditions; ASA I with a a mild respiratory condition, pregnancy, and/or active allergies as well as current smoker and/or social alcohol drinker including obesity (30 < BMI < 40). May need medical consultation before all dental care.
Note: Patients who demonstrate a more extreme anxiety and fear toward dentistry have a baseline of ASA II even before their medical history is considered; that situation can raise the classification system for that patient.
ASA III
Patients have one or more moderate to severe systemic diseases that limits activity, but is not incapacitating. Patients are able to walk up one flight of stairs or two level city blocks, but will have to stop enroute because of distress and thus have substantive functional limitations. If dental care is indicated, stress reduction protocol and other treatment modifications are indicated. This classification represents a "yellow flag" for treatment, with a slight to strong warning flag indicating to proceed with extreme caution during dental treatment. Examples: History of more than three months of angina pectoris, transient ischemic attack, myocardial infarction, cerebrovascular accident, congestive heart failure, coronary artery disease with stents, slight chronic obstructive pulmonary disease, and poorly controlled insulin dependent diabetes or hypertension as well as morbid obesity (BMI ≥40), active hepatitis, alcohol dependence or abuse, implanted pacemaker, moderate reduction of ejection fraction, end-stage renal disease undergoing regularly scheduled dialysis. Will need medical consultation before all dental care.
ASA IV
Patients have severe systemic disease that limits activity and is a constant threat to life. Patients are unable to walk up one flight of stairs or two level city blocks. Distress is present even at rest. Patients pose significant risk since patients in this category have a severe medical problem of greater importance to the patient than the planned dental treatment. Whenever possible, planned dental treatment should be postponed until such time as the patient's medical condition has improved to at least an ASA III classification. This classification represents a "red flag", with a strong warning flag indicating that the risk involved in treating the patient is too great to allow planned dental care to proceed. Examples: History of less than three months of unstable angina pectoris, myocardial infarction, cerebrovascular accident, severe congestive heart failure, coronary artery disease with stents, ongoing ischemia or severe valve dysfunction, severe reduction of ejection fraction, sepsis, disseminated intravascular coagulation, moderate to severe chronic obstructive pulmonary disease, including uncontrolled diabetes, hypertension, epilepsy, or thyroid condition as well as renal failure with refractory ascites and end-stage renal disease not undergoing regularly scheduled dialysis. If emergency treatment is needed, medical consultation is still indicated.
ASA V
Patients are moribund and are not expected to survive more than 24 hours with or without an operation. These patients are almost always hospitalized, terminally ill patients. Elective dental treatment is definitely contraindicated; however, emergency care, in the realm of palliative treatment may be necessary. This classification represents a “red flag" for dental care and any care is done in a hospital situation. Examples: History of 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
Clinically dead patients being maintained for harvesting of organs.
EMERGENCY CARE AND PREGNANCY CONCERNS
ASA-E: Emergency operation of any variety; used to modify one of the above classifications, i.e., ASA III-E.
ASA-P: Pregnant patient; used to modify one of the above classifications, i.e., ASA III-P.
Discussion and Summary:
The ASA Physical Status Classification System has been in use for over 60 years for medical professionals and somewhat less for dental professionals. The purpose of the system is to more accurately assess and communicate a patient’s medical risk within their dental records as well as to other health professionals. The classification system alone does not predict the dental treatment risks, but used with other factors (e.g., type of treatment, frailty, and level of deconditioning), it can be helpful in predicting these risks. The definitions and examples shown in the table above are only guidelines for the clinician. Assigning a level is a clinical decision based on multiple factors.
While the classification may initially be determined at various times during the the initial assessment of the patient, the final assignment of classification is made on the day of dental treatment after reevaluating the patient. Thus is important to note that ASA status can change as medical history changes so it is important to update before all dental procedures.
Part of the prevention of office medical emergencies with patients at high risk requires modification of treatment procedures, and the specific modifications will vary according to the type of risk. However, it is almost universally the case when working with a patient at high risk for a medical emergency that stress must be reduced before, during, and after the oral health care treatment. The American Dental Association (ADA) strongly recommends stress reduction techniques in the oral health care setting, see also their Tips.
This classification system is modified by MJ Fehrenbach, RDH, MS, from the American Society of Anesthesiologists (Updated 2020) with a downloadable PDF available; see link also for pediatric examples. In addition, Medical Emergencies in the Dental Office (8th edition, Malamed, Mosby, 2022) is similar but uses traffic lights instead of the usual medical record flags (see pages 53- 56). See Wikipedia that sites this chart for more information. See also Elsevier's latest notes on it.
Updated 10/1/2024 Fehrenbach and Associates