An established patient is defined as one who has received professional services from the same...

For outpatient E/M reporting, “new vs. established patient” status is determined using a lookback period based on prior professional services. Anestablished patientis one who has received face-to-face (or other qualifying professional) services from the same physician or another physician/qualified healthcare professional of thesame specialty and subspecialtyin thesame group practicewithin theprevious three years. This definition is critical for compliant coding because it drives which E/M code family is available (new patient codes vs established patient codes), and it affects relative valuation, documentation expectations, and audit risk. Outpatient CDI education emphasizes helping providers document the medical necessity and complexity of the visit regardless of patient status, but also ensuring correct administrative classification so coders select the correct code set. The three-year window prevents inappropriate use of new patient codes when the patient has an ongoing clinical relationship with the practice/specialty, supporting accurate reimbursement and consistent reporting.