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77066

Diagnostic Mammogram, One Breast

Code Description

CPT code 77066 is used to report diagnostic mammography performed on both breasts. The service includes computer-aided detection (CAD) when performed.

Unlike routine screening mammography, diagnostic mammography is performed to evaluate a specific symptom, abnormal finding, or area of concern. It may be ordered following an abnormal screening mammogram or to evaluate symptoms such as a breast lump, focal breast pain, or suspicious nipple discharge.

When to Use 77066

Common examples include:

  • Evaluation of abnormalities involving both breasts

  • Follow-up after an abnormal screening mammogram

  • Evaluation of breast symptoms requiring bilateral imaging

  • Short-term follow-up of previous diagnostic findings

  • Surveillance when diagnostic mammography is medically appropriate

  • Diagnostic comparison of both breasts

Documentation Requirements

Documentation should include:

  • Reason for the diagnostic examination

  • Symptoms or abnormal findings being evaluated

  • Confirmation that both breasts were examined

  • Medical necessity for diagnostic imaging

  • Radiologist interpretation

  • Diagnostic findings and recommendations

Common Billing Mistakes

Common billing mistakes include:

  • Reporting 77066 when only one breast was examined

  • Confusing diagnostic mammography with screening mammography

  • Failing to document the reason for the diagnostic examination

  • Incorrect use of professional or technical component modifiers

  • Insufficient documentation supporting medical necessity

Related CPT Codes
77065

Diagnostic Mammogram, One Breast

77067

Screening Mammogram

76641

Complete Breast Ultrasound

FAQ

What does CPT code 77066 cover?

CPT code 77066 reports bilateral diagnostic mammography, meaning diagnostic imaging of both breasts. CAD is included when performed.

What is the difference between CPT 77065 and 77066?

CPT 77065 reports unilateral diagnostic mammography involving one breast, while CPT 77066 reports bilateral diagnostic mammography involving both breasts.

What is the difference between CPT 77066 and 77067?

CPT 77066 is used for bilateral diagnostic mammography, while CPT 77067 is used for bilateral screening mammography. Diagnostic mammography evaluates symptoms or abnormal findings, while screening mammography is generally performed for early detection in patients without signs or symptoms of breast disease.

Can Modifier 26 be used with CPT 77066?

Modifier 26 may be reported when the provider bills only for the professional component of the service, such as interpreting the mammogram and preparing the written report.

Procedure Type

Diagnostic Mammography

Body Area

Laterality

Breast

Bilateral