Outpatient Therapy Code Modifiers - GN, GO, GP

Therapy Modifiers

All claims containing a procedure code from the following list of “Applicable Outpatient Rehabilitation HCPCS Codes” should contain one of the therapy modifiers to distinguish the discipline of the plan of care under which the service is delivered:

GN Services delivered under an outpatient speech-language pathology plan of care;

GO Services delivered under an outpatient occupational therapy plan of care; or,

GP Services delivered under an outpatient physical therapy plan of care.

The exception to this is: Claims from physicians (all specialty codes) and nonphysician practitioners, including specialty codes “50,” “89,” and “97,” may be processed without therapy modifiers for codes marked (+) sometimes only therapy codes.

Use Modifiers to identify therapy services whether or not financial limitations are in effect. When limitations are in effect, the national Common Working File (CWF) database tracks the financial limitation based on the presence of therapy modifiers. Providers/suppliers must continue to report one of these modifiers for any therapy code on the list of applicable therapy codes except as noted above. These modifiers do not allow a provider to deliver services that they are not qualified and recognized by Medicare to perform.

This is applicable to all claims from physicians, NPPs, PTPPs, OTPPs, CORFs, OPTs, hospitals, SNFs, and any others billing for physical therapy, speech-language pathology or occupational therapy services as noted on the applicable code list below.


Modifiers refer only to services provided under plans of care for physical therapy, occupational therapy and speech-language pathology services. For example, respiratory therapy services, or nutrition therapy services shall not be represented by the codes, which require GN, GO, and GP modifiers.


For all other claims submitted by physicians or nonphysician practitioners (as noted above) containing these applicable HCPCS codes without therapy modifiers, the claim will be returned as unprocessable.


If specialty codes “65” and “67” are present on the claim and an applicable HCPCS code is without one of the therapy modifiers (GN, GO, or GP) the claim will be returned as unprocessable.


The CWF will capture the amount and apply it to the limitation whenever a service is billed using the GN, GO, or GP modifier.