We have received a denial for E/M code 99204 from a managed care plan stating that the patient was an established patient based on a Diagnostic Assessment 90791, 90785 we did about 10 days prior to the E/M.

My provider wants me to appeal based on the clip from the CMS guide to billing E/M: New Patient: An individual who did not receive any professional services from the physician/non-physician practitioner (NPP) or another physician of the same specialty who belongs to the same group practice within the previous 3 years.

We are a mental health organization and he states that since our providers are not "physicians" then they cannot use the diagnostic assessment as a previously professional services. I have argued that the diagnostic assessment was an encounter and therefore makes this patient established. How can I appeal something that I think is incorrect.

Am I wrong in this matter and should I still appeal?