HCPCS code G0206 – Diagnostic mammography, unilateral

Key takeaways

HCPCS code G0206 described diagnostic mammography of one breast, including computer-aided detection (CAD) when performed.

CMS deleted G0206 effective January 1, 2018, so it cannot be reported for any date of service from that day on.

CPT 77065 replaced G0206 for every payer, Medicare included. CPT 77066 covers bilateral diagnostic exams and 77067 covers screening.

Append LT or RT to 77065, and keep screening diagnosis codes such as Z12.31 off diagnostic claims.

Pabau, the practice management platform we build, holds claims for review so a retired code or a missing modifier is caught before submission.

HCPCS code G0206: Definition and code status

HCPCS code G0206 was the Level II code for diagnostic mammography, unilateral, including computer-aided detection when performed. CMS deleted it effective January 1, 2018, and CPT 77065 replaced it for every payer, Medicare included.

G0206 sat in the G0000–G9999 range of the HCPCS Level II system, which CMS reserves for procedures and professional services (temporary). Temporary G codes cover services that have no CPT code yet. Once the AMA publishes a CPT code for the same service, CMS usually retires the G code.

That is what happened here. CPT introduced 77065, 77066 and 77067 in 2017, and Medicare moved to them a year later. Every other code page in our HCPCS code library follows the same rule. The date of service decides which code is valid.

G0206 code details at a glance

Is G0206 still valid? Code status and the 2018 deletion

No. G0206 cannot be reported for dates of service on or after January 1, 2018. CMS deleted it together with G0204 and G0202 in Transmittal R3844CP, the change request behind MLN Matters article MM10181.

The G codes had a short second life. The AMA created 77065, 77066 and 77067 for 2017, but CMS could not process them that year. Its mammography coding FAQ told practitioners to keep reporting G0202, G0204 and G0206 for 2017 dates of service only.

From 2018 on, Medicare and commercial payers use the same CPT codes. The old split, with G codes for Medicare and CPT codes for commercial plans, no longer exists. A claim that still carries G0206 today is rejected as an invalid code.

Replacement codes: What to bill instead of G0206

Bill CPT 77065 for a diagnostic mammogram of one breast, and 77066 for a diagnostic exam of both breasts. Screening mammography moved to CPT 77067. Each replacement keeps CAD inside the descriptor, so CAD is never billed separately.

Diagnostic mammography is not a preventive service. A preventive screening uses 77067, while 77065 and 77066 are ordered because of a clinical sign, a symptom or an abnormal earlier result. That distinction drives the diagnosis code, the modifiers and what the patient pays. Two questions route any mammogram to its current code.

How to bill a unilateral diagnostic mammogram with 77065

The billing advice that used to apply to G0206 now applies to 77065. Three details decide whether the claim is paid on the first pass.

Laterality: LT or RT

CPT 77065 describes one breast, so the claim must show which one. Append LT for the left breast or RT for the right. The modifier must match the side named in the order and in the radiology report.

Check your payer manual for its exact rule, because some plans treat a missing modifier as an automatic denial. Adding LT or RT on every 77065 claim costs nothing and removes the question. If both breasts were imaged diagnostically, the right code is 77066 rather than 77065 with two modifiers.

Diagnosis code: Keep Z12.31 off diagnostic claims

Z12.31 is the ICD-10-CM code for an encounter for screening mammogram for malignant neoplasm of breast. It belongs on a 77067 screening claim. On a 77065 claim it creates an indication mismatch, and payers deny it.

Report the finding that prompted the exam instead. Examples include a code from the N63 category for a breast lump, or N64.51 for induration of breast. The clinical note has to support whichever code you choose.

Same-day screening and diagnostic exams: The GG modifier

Sometimes a screening mammogram shows a finding and the radiologist runs a diagnostic exam the same day. Medicare pays for both when the GG modifier is appended to the diagnostic code. Report 77067 for the screening, then 77065 or 77066 with GG for the diagnostic exam.

Confirm your Medicare Administrative Contractor (MAC) has no local instruction that changes this sequence. Commercial plans set their own same-day rules, so check each payer manual as well.

Tomosynthesis: G0279 pairs with 77065 or 77066

HCPCS G0279 is still active. It reports diagnostic digital breast tomosynthesis (DBT), also called 3D mammography, unilateral or bilateral. Since 2018 it is listed in addition to 77065 or 77066, never with G0206.

For a 3D diagnostic exam of one breast, report 77065 with LT or RT, then G0279. Screening tomosynthesis uses a different add-on, CPT 77063, which pairs with 77067. CMS payment rules for G0279 have changed through annual fee schedule rulemaking, so check the current rule before you bill.

Medicare coverage for diagnostic mammography under 77065

Medicare Part B covers a diagnostic mammogram when a treating physician orders it for a clinical reason. According to Medicare.gov, the Part B deductible applies and the patient pays 20% of the Medicare-approved amount. Preventive screening, by contrast, carries no cost-sharing for eligible patients.

• Frequency: Medicare.gov states diagnostic mammograms can be covered more often than once a year when the doctor orders them. Each exam still needs documented medical necessity. Verify the current wording with CMS before you quote it to patients.
• Prior authorization: Diagnostic mammography is not on Original Medicare’s prior authorization lists at the time of writing. Verify with CMS before relying on that, because the lists change. Medicare Advantage and commercial plans set their own rules.
• Facility certification: The imaging facility must hold current Mammography Quality Standards Act (MQSA) certification. Claims from a facility without it are not covered.
• Payment rates: Rates for 77065 change every year. Look them up in the current Medicare Physician Fee Schedule rather than relying on prior-year figures.

Documentation requirements for 77065 claims

A well-documented 77065 claim answers four questions before a reviewer asks them. Who ordered the exam, why, which side, and what did the radiologist find?

• Ordering provider: The order names the ordering physician and their NPI. It states a specific clinical indication, such as a palpable mass or nipple discharge.
• Diagnostic indication: The medical record supports the ICD-10-CM code on the claim. A breast lump code needs a note describing its location, size and how it was found.
• Laterality: The order, the report and the LT or RT modifier all name the same breast. A mismatch between them is an audit red flag.
• Interpretation: A signed, dated radiology report uses Breast Imaging Reporting and Data System (BI-RADS) categories to record the findings and the recommendation.

A claim can meet every clean claim requirement and still deny on medical necessity review. That happens when the clinical note does not support the diagnostic indication, so both layers need checking.

Common billing errors on legacy G0206 claims

Most mammography denials trace back to a short list of causes. The table maps each one to its fix, and a structured approach to denial management helps you spot a pattern before it repeats.

Any old G0206 claim still open in your system is past the Medicare timely filing limit, which is one year from the date of service. Write it off or close it out rather than rebilling it.

How Pabau keeps retired mammography codes out of your claims

Code deletions rarely announce themselves inside a billing team. A charge master entry or a saved order set keeps G0206 alive long after CMS retired it. The first sign is usually a run of rejections.

Pabau’s error-catching claims management holds each claim for review before it goes out. Billing staff see the procedure code, the modifiers and the linked diagnosis codes on one screen while the claim is still editable. Denials that do land are grouped by reason code, so a pattern shows up within days.

Order details and authorization notes sit on the patient record rather than in a separate folder. That keeps the laterality and the clinical indication on hand when the claim is built.

Catch retired codes before they reach a payer

Pabau holds claims for review and shows codes, modifiers and diagnoses on one screen. Denials are tracked by reason code, so a deleted code like G0206 never turns into a month of rework.

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Conclusion

G0206 has been gone since January 1, 2018. Any order set or charge master that still maps to it is costing the practice paid claims. Report 77065 for one breast and 77066 for both, with the same laterality and diagnosis-code discipline G0206 always needed.

The lesson outlasts this code. A temporary G code is designed to be replaced, so check the date of service before you trust any mammography code. Book a demo to see how Pabau catches retired codes before a claim goes out.

Continue your research

Need to understand how claims move from code to payment? What is medical billing explains the full claim lifecycle from encounter to remittance.

Want to keep up with annual code changes across payers? Medical billing compliance covers the rules practices follow as codes and payer policies change.

Looking at the bigger picture of claim performance? Revenue cycle management explained covers the process from charge capture through payment posting.

Coding the screening exam G0206 sat beside? HCPCS code G0202 covers the deleted screening code that CPT 77067 replaced.

Adding 3D imaging to a screening mammogram? CPT code 77063 explains the screening tomosynthesis add-on that pairs with 77067.

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