April 30, 2026
New Modifier Requirements for Functional Electrical Stimulation (FES)
For dates of service on or after June 1, 2026, suppliers must add the SC, GA, GY, or GZ modifier on all claims for Functional Electric Stimulation (FES). This applies to the following codes:
- E0764 – functional neuromuscular stimulation, transcutaneous stimulation of sequential muscle groups of ambulation with computer control, used for walking by spinal cord injured, entire system, after completion of training program
- E0770 – functional electrical stimulator, transcutaneous stimulation of nerve and/or muscle groups, any type, complete system, not otherwise specified
The SC modifier (medically necessary service or supply) indicates the reasonable and necessary requirements outlined in the National Coverage Determinations Manual 100-03 Chapter 1, Part 2, Section 160.12
have been met. Alternatively, the GA, GY, or GZ indicate the applicable payment criteria are not met.
Claim lines billed without a SC, GA, GY or GZ modifier will be rejected for missing information and may be resubmitted with the appropriate modifier.
For more information, see the Functional Electrical Stimulation (FES) – Coverage and HCPCS Coding – Revised article.

