Place of Service Code

A two-digit CMS code on the claim indicating where the service was rendered. Key codes for behavioral health: POS 11 (Office — in-person sessions at a private practice); POS 02 (Telehealth — originating site); POS 10 (Telehealth — patient's home, the most common code since COVID-era waivers). Mismatching POS code and telehealth modifiers is a common billing error generating CO-4 or CO-16 denials.