HCPCS Modifier GG

Published 07/16/2020

Description
HCPCS modifier GG is used to report performance and payment of a screening mammography and diagnostic mammography on the same patient on the same day.

Guidelines and Instructions
Medicare allows additional mammogram films to be performed without an additional order from the treating physician.

  • When the radiologist interpretation of screening mammography results in the performance of diagnostic mammography on the same day for the same patient, both tests will be reimbursed
  • Submit HCPCS modifier GG with the diagnostic mammography code
  • This modifier is required for tracking and data collection purposes
This modifier may be submitted with the following codes:
  • CPT codes: 77065 and 77066 
  • HCPCS codes: G0204 and G0206 (Note: G0204 and G0206 are no longer valid for dates of service January 1, 2018, and after)

Reference: CMS Internet Only Manual: Claims Processing Manual 100-4, Chapter 18 Preventive and Screening Services, Section 20 Mammography (PDF, 1.22 MB).