Radiology departments process hundreds of mammography cases every day. While breast imaging is clinically structured, mammography coding can be more complex. Mammography billing errors and claim denials can be caused by incorrect CPT selection, diagnosis errors, NCCI conflicts, modifier issues and documentation gaps.

For accurate breast imaging coding, coders must understand the patient’s indication, type of examination, laterality, diagnosis, modifiers, and payer requirements. This guide covers common errors in mammography coding, mammography procedure codes, billing requirements, and mammography coding guidelines.

What Is Mammography? A Quick Clinical Overview

Mammography is a low dose x-ray imaging procedure that is utilized to examine breast tissue. Understanding the types of mammography is important because screening and diagnostic studies have different coding considerations.

Common types of mammography include:

• Screening Mammography: Routine imaging for patients without documented breast symptom or known abnormality
• Diagnostic Mammography: Used when there are symptoms or an abnormal screening result that needs further evaluation.
• Digital Breast Tomosynthesis (DBT): 3D imaging that takes pictures from multiple angles to reduce tissue overlap.
• Contrast-Enhanced Mammography (CEM):  Uses contrast material in conjunction with mammographic imaging for certain clinical indications.
• Additional Diagnostic Views Spot:  compression, magnification and other views may be performed to evaluate a specific finding.

Appropriate code should be selected based on the types of mammography identified from the clinical documentation.

Mammogram CPT Codes: What Coders Must Know in 2026

Correct mammogram CPT codes are the foundation of accurate mammography billing.

CMS identifies 77065 and 77066 for diagnostic mammography and 77067 for screening mammography bilateral. It also lists +77063 and G0279 as appropriate add-on codes for screening and diagnostic tomosynthesis.

Screening Mammography CPT Codes

Primary screening mammography CPT codes include 77067 for bilateral screening mammography. Separate reporting of CPT 77063 for bilateral screening breast tomosynthesis is recommended when applicable.

Diagnostic Mammography CPT Codes

The primary diagnostic mammography CPT codes are:

• 77065 – Diagnostic mammography, unilateral
• 77066 – Diagnostic mammography, bilateral

The appropriate diagnostic mammography CPT codes should be selected according to the documented service and laterality.

Mammography Indications by Age and Clinical Condition

Mammography indications age can vary based on screening recommendations, risk factors, and payer requirements.  Age should not be the sole consideration in determining the appropriate billing code.

Common screening mammography indications include routine breast cancer screening in eligible asymptomatic patients.

Common breast mammography indications for diagnostic evaluation include:

• Breast lump 
• Breast pain
• Nipple discharge
• Breast asymmetry
• Abnormal screening result
• Suspicious calcifications
• Architectural distortion

When reviewing mammography indications radiology documentation, coders should identify why the examination was performed and whether it was screening or diagnostic.

The mammography indications age should therefore be considered together with the patient’s clinical history and payer policy rather than used as an automatic coding rule.

For screening mammography, CMS identifies Z12.31 as the diagnosis for an encounter for screening mammogram for malignant neoplasm of breast.

Top Mammography Coding Errors in High-Volume Radiology

High examination volumes can multiply small mammography coding errors.

1. Screening vs. Diagnostic Miscoding

A common mistake is the use of a screening code when the patient has a documented symptom or abnormality requiring diagnostic evaluation.

2. Incorrect Mammography Modifier GG

Mammography modifier GG is used when a screening mammogram and diagnostic mammogram are performed on the same patient on the same day under Medicare billing instructions. CMS adds that the diagnostic mammography code is combined with modifier GG for tracking purposes.

The use of the mammography modifier GG is appropriate only when the requirements apply.

3. NCCI Edit Conflicts

NCCI edits mammography claims to prevent the incorrect reporting of some code combinations.

Coders should verify current NCCI edit mammography requirements prior to reporting multiple services together. Improper unbundling of procedures can result in mammography claim denials.

4. Incorrect DX Code for Abnormal Mammogram

If the exam reveals an abnormality, select the dx code abnormal mammogram based on the documented finding and applicable ICD-10-CM guidelines.

If an imaging finding is suspicious, the dx code abnormal mammogram should not necessarily mean cancer.

Proper selection of the dx code abnormal mammogram helps support medical necessity and decreases unnecessary denials.

5. Contrast Mammography Billing Gaps

Contrast mammography indications should be clearly documented when contrast-enhanced mammography is performed.

In cases where contrast mammography indications and documentation requirements are different by service and payer, coders should review the actual procedure rather than automatically assigning a standard mammography code.

Mammography Coding Guidelines

The mammography coding guidelines should be reviewed using current CPT, HCPCS, ICD-10-CM, CMS, NCCI, and payer-specific resources.

CMS currently identifies:

• 77065 – Diagnostic unilateral mammography
• 77066 – Diagnostic bilateral mammography
• 77067 – Bilateral screening mammography
• 77063 – Bilateral screening breast tomosynthesis
• G0279 – Diagnostic digital breast tomosynthesis

CMS also states that CAD is included when performed in the descriptions of 77065, 77066, and 77067.

Therefore, current mammography coding guidelines should be used instead of older references that may contain retired Medicare G0202 coding information.

Mammography Billing Guidelines

Following current mammography billing guidelines helps radiology teams reduce incorrect claims.

Before submission, verify:

1. Screening or diagnostic status
2. Correct mammography procedure codes
3. Laterality
4. Diagnosis
5. Clinical indication
6. Applicable modifier
7. Tomosynthesis reporting
8. NCCI edits
9. Payer requirements
10. Supporting documentation

Strong mammography billing guidelines should be incorporated into the organization’s coding checklist and quality-control process.

Mammography Billing Errors and Claim Denials

Common mammography billing errors include:

• Incorrect CPT selection
• Wrong diagnosis
• Incorrect laterality
• Missing modifier
• Incorrect tomosynthesis reporting
• NCCI conflicts
• Insufficient documentation
• Incorrect payer-specific billing

Such mammography billing errors can lead to mammography claim denials, payment delays, and additional rework.

Some of the common mammography claim denials include medical necessity, diagnosis not stated correctly, modifiers missing, CPT codes incorrect or documentation problems.

Organizations can identify weaknesses in their coding Mammography workflow efficiency by reviewing recurrent mammography claim denials.

How Automation Can Improve Mammography Coding

High-volume radiology operations can use automation to support mammography coding and reduce repetitive manual work.

AI-assisted workflows can help with:

• CPT code identification
• Screening versus diagnostic classification
• NCCI validation
• Modifier identification
• ICD-10-CM suggestions
• Documentation review
• Denial-risk identification

Automation can also support breast imaging coding by analyzing radiology documentation and identifying potential coding inconsistencies before claims are submitted.

For teams experiencing recurring mammography coding errors, automated validation can provide an additional quality-control layer while allowing experienced coders to focus on complex cases.

Final Thoughts

Accurate mammography coding is more than knowing the individual CPT codes. Radiology teams need to understand the types of mammography, indications for breast mammography, indications for mammography radiology, requirements for diagnosis, NCCI rules, modifiers, and payer-specific documentation.

According to the current mammography coding guidelines and mammography billing guidelines can help cut down on mammography billing errors, improve claim accuracy, and reduce mammography claim denials.

When you combine experienced coders with intelligent automation in high-volume radiology environments, you can increase coding consistency, accelerate billing workflows and deliver cleaner claims.