To the Editor:
We read with great interest the review article on the American Society of Anesthesiologists (ASA; Schaumburg, Illinois) Physical Status Classification System by Horvath et al.1 The review presents in excellent detail the origin, evolution, and current state of the ASA Physical Status system. Further, the authors describe the recent addition of clinical examples to help clarify the classifications. These examples have been useful to provide some consistency in the assignment of ASA Physical Status classifications by anesthesia-trained and non–anesthesia-trained clinicians2 and have been demonstrated to improve communication about patient status to anesthesia providers when assessments are performed by anesthesiologists in preanesthesia clinic settings and before the day of surgery.3
As an extension of the historical perspective they have given, the authors also consider whether further refinements or more granular categories might be of value. In proposing that the ASA and anesthesia community revise the ASA Physical Status system, we want to provide some additional background information about the current status of the system and its implications. Although the ASA Physical Status system is used by many anesthesia and nonanesthesia clinicians in the United States and around the world for purposes unrelated to the initial purpose for which it was created, in the United States, physical status modifiers based on (and identical to) the ASA classification system are part of the Current Procedural Terminology, which is a product of the American Medical Association (Chicago, Illinois).4 These billing modifiers are used to justify additional payment by some payers based on the physical status of patients receiving anesthesia care. If the ASA determined that modifications to the current system were warranted, the society would have the ability to make changes to it. However, any changes proposed by the ASA will not impact payment unless the ASA requested revisions to the Current Procedural Terminology–defined physical status modifiers. To do so, the ASA would have to submit an application for a code change at the Current Procedural Terminology level and then a valuation through the American Medical Association Relative Value System Update Committee.5 Although ASA can give input, the Current Procedural Terminology Editorial Board and the American Medical Association Relative Value System Update Committee would make final decisions on the physical status billing modifiers (the definitions, categories, and valuation). This request and approval process takes at least 3 yr to be implemented.
Based on this historical background, the ASA, through the House of Delegates and with support and recommendations provided by the ASA Committee on Economics, chose to provide additional examples to better illustrate the application of the definitions and the determination of appropriate ASA Physical Status assignment rather than propose revisions to the categories and definitions. As noted in the review, the initial examples were adopted in 2014 specifically for adult patients. In 2020, examples for pediatric patients and obstetric patients were added with input from the ASA Committees on Pediatric Anesthesia and on Obstetric Anesthesia.
The authors are all members of the American Society of Anesthesiologists (ASA) Committee on Economics (Schaumburg, Illinois). S. Merrick is the ASA staff member on the committee.