Medical Decision Making: Guide to Improved CPT Coding

Document Type


Publication Date



Background: The Current Procedural Terminology (CPT) coding system for office visits, which has been in use since 1995, has not been well studied, but it is generally agreed that the system contains much room for error. In fact, the available literature suggests that only slightly more than half of physicians will agree on the same CPT code for a given visit, and only 60% of professional coders will agree on the same code for a particular visit. In addition, the criteria used to assign a code are often related to the amount of written documentation. The goal of this study was to evaluate two novel methods to assess if the most appropriate CPT code is used: the level of medical decision making, or the sum of all problems mentioned by the patient during the visit.

Methods: The authors–a professional coder, a residency faculty member, and a PGY-3 family medicine resident–reviewed 351 randomly selected visit notes from two residency programs in the Northeast Tennessee region for the level of documentation, the level of medical decision making, and the total number of problems addressed. The authors assigned appropriate CPT codes at each of those three levels.

Results: Substantial undercoding occurred at each of the three levels. Approximately 33% of visits were undercoded based on the written documentation. Approximately 50% of the visits were undercoded based on the level of documented medical decision making. Approximately 80% of the visits were undercoded based on the total number of problems which the patient presented during the visit. Interrater agreement was fair, and similar to that noted in other coding studies.

Conclusions: Undercoding is not only common in a family medicine residency program but it also occurs at levels that would not be evident from a simple audit of the documentation on the visit note. Undercoding also occurs from not exploring problems mentioned by the patient and not documenting additional work that was performed. Family physicians may benefit from minor alterations in their documentation of office visit notes.

Key Points:

* All previous studies of CPT coding have audited the written encounter note.
* Medical decision making (MDM) is the most appropriate basis for selecting the CPT code for an office visit, as long as the history or the physical exam documentation also support that level.
* Using MDM to retrospectively audit office visit notes showed that 50% of visits were undercoded. A small amount of additional documentation would allow the higher code.
* Addressing all patient-mentioned problems during the visit, although clearly more time-consuming, would allow a higher CPT code to be used for 80% of the audited visits.