By CPT definition, a new patient is "one who has not received any professional services from the physician, or another physician of the same specialty who belongs to the same group practice, within the past three years." By contrast, an established patient has received professional services from the physician or another physician in the same group and the same specialty within the prior three years.
The distinction between new and established patients applies only to the categories of evaluation and management (E/M) services titled "Office or Other Outpatient Services" and "Preventive Medicine Services," but as a family physician, most of the codes you submit fall into these categories, and the definition is hard to incorporate into your coding habits. This article will explain why the difference matters and describe an approach you can use to make the definition easier to apply.
For the complete article, go to http://www.aafp.org/fpm/20030900/33unde.html