Description
The description of HCPCS modifier CN is 100 percent impaired, limited or restricted.

Guidelines and Instructions

• A modifier must be used to report the severity/complexity for that functional measure for each non-payable therapy G-code
• The severity modifiers reflect the patient’s percentage of functional impairment as determined by the therapist, physician or nonphysician practitioner (NPP) furnishing the therapy services
• The patient’s current status, the anticipated goal status, and the discharge status are reported via the appropriate severity modifiers. The seven modifiers are defined in the following table:

Required Reporting of Functional G-codes and Severity Modifiers
The functional G-codes and corresponding severity modifiers listed above are used in the required reporting on specified therapy claims for certain dates of service (DOS). Only one functional limitation shall be reported at a given time for each related therapy plan of care (POC). However, functional reporting is required on claims throughout the entire episode of care; so, there will be instances where two or more functional limitations will be reported for one beneficiary’s POC, just not during the same time frame. In these situations, where reporting on the first reported functional limitation is complete and the need for treatment continues, reporting is required for a second functional limitation using another set of G-codes. Thus, reporting on more than one functional limitation may be required for some beneficiaries, but not simultaneously.

Functional reporting, using the G-codes and modifiers, is required on therapy claims for certain DOS:

• At the outset of a therapy episode of care, i.e., on the DOS for the initial therapy service
• At least once every 10 treatment days — which is the same as the newly-revised progress reporting period — the functional reporting is required on the claim for services on same DOS that the services related to the progress report are furnished
• The same DOS that an evaluative procedure, including a re-evaluative one, is submitted on the claim
• At the time of discharge from the therapy episode of care, if data is available
• On the same DOS the reporting of a particular functional limitation is ended, in cases where the need for further therapy is necessary

Reference: MLN Matters 8005 (PDF, 345 KB).