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77067 vs 77066: Screening vs Diagnostic Mammography

Last Updated: December 31, 2025

Mixing up a screening mammogram (77067 ↗) with a diagnostic mammogram (77066 ↗) is one of the biggest compliance and patient satisfaction risks in radiology, because screening mammograms are free for the patient (no copay/deductible).

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2026 Medicare National Fee (77067): Non-Facility (Office): $168.59 · Facility (Hospital): $168.59
✓ 156 Medicare-Approved ICD-10 Diagnoses on file for 77067:

Screening vs Diagnostic

  • 77067 (Screening): The patient is completely asymptomatic. This is their routine annual exam. It is covered 100% under the ACA/Medicare preventive rules.
  • 77066 (Diagnostic): The patient has a sign, symptom, or abnormality (e.g., a breast lump, pain, or returning to check an abnormal finding from a previous screen). This is subject to copays and deductibles.

Medical Necessity: The Z Code

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For a screening mammogram (77067), you MUST use a screening diagnosis code like Z12.31 ↗ (Encounter for screening mammogram for malignant neoplasm of breast). Using a symptom code will result in a denial.

Modifier GG and GH

If a screening mammogram turns into a diagnostic mammogram on the same day (because the tech found an abnormality and immediately did diagnostic views), you bill both, but must append Modifier GG to the diagnostic code.

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