Medical Decision Making (MDM) is one of the three “key components” of determining the level of an evaluation and management (E/M) service. It is probably the most difficult component of an E/M service to review. MDM is where the providers thought process is quantified and most often the primary role in determining the correct level of service or E/M code.

In a previous blog I wrote, "Seeing the “Gray” in Evaluation and Management Coding – Chief Complaint and History of Present Illness," I had started a dialogue related to Chief Complaint (CC) and History of Present Illness (HPI) gray areas. In this edition I hope to continue the conversation as it relates to review of systems (ROS) and past family social history (PFSH).

Many health care professionals use E&M coding grids to assist with the application of E&M codes. In it’s Evaluation and Management Services Guide, CMS indicates that for determining the complexity of medical decision making, “The number of possible diagnoses and/or the number of management options that must be considered is based on: