Answer 
Therapy services provided by a chiropractor, although non-covered, must be submitted according to therapy guidelines. Therefore, please be sure to include one of the therapy modifiers defined below. Therapy services submitted without the appropriate therapy modifier, including services submitted with HCPCS modifier GY, will be rejected as unprocessable.

• HCPCS modifier GN — Services delivered under an outpatient speech-language pathology plan of care
• HCPCS modifier GO — Services delivered under an outpatient occupational therapy plan of care
• HCPCS modifier GP — Services delivered under an outpatient physical therapy plan of care

A list of codes that require therapy modifiers is available on the CMS website.