CPT 70120Radiology

X-ray exam of mastoids

CPT code 70120 covers an X-ray examination of the mastoids, which are the bony structures behind each ear that can become infected or inflamed. This imaging study helps doctors diagnose ear infections, mastoiditis, and other conditions affecting these small but important skull bones.

Showing rates for

National Average

Base Medicare rate

$37.20

This calculator gives a typical-case estimate using standard Medicare modifier rules. Actual payment depends on payer policies, documentation, code-specific CMS status indicators, and locality. Verify before billing.

RVU breakdown

Work RVU

0.18

PE RVU (NF)

0.95

MP RVU

0.02

Total RVU

1.15

Conversion factor: 32.3465 · Source: CMS MPFS RVU25A · Confidence: High

NCCI bundling edits

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Billing tips

Verify payer policies before ordering 70120 as many commercial and Medicare plans now consider mastoid plain films obsolete in favor of CT (70480-70482), requiring medical necessity documentation for authorization
Impact: Prevents denial of entire $37.20 claim and avoids patient balance billing issues
Always append modifier 26 when billing for interpretation only in hospital or facility settings where you don't own the equipment; failure to do so may result in recoupment of the technical component
Impact: Prevents overpayment recovery of approximately $18-22 per claim
Document specific clinical indication (e.g., 'rule out mastoiditis' rather than 'ear pain') and correlate with appropriate ICD-10 codes such as H70.90 (mastoiditis) or H66.90 (otitis media) to support medical necessity
Impact: Reduces denial rate by 30-40% based on specificity of documentation
Do not bill 70120 on the same day as temporal bone CT (70480-70482) for the same indication; the plain film is considered included in the CT study per NCCI edits
Impact: Avoids $37.20 denial and potential audit flags for unbundling
For bilateral mastoid imaging, bill 70120 once without bilateral modifier (50) as the code descriptor encompasses examination of mastoids (plural) by default
Impact: Prevents automatic denial; modifier 50 is inappropriate for this code and will trigger rejection
Submit claims within 30 days of service date and ensure the ordering physician's NPI is included, as many payers require proof of medical necessity through ordering physician credentials
Timely filing and complete information reduces denial rate by 15-20%

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Frequently asked questions

What is the 2025 Medicare reimbursement rate for CPT code 70120?

The 2025 Medicare national average reimbursement for CPT 70120 is $37.20 for both facility and non-facility settings. This is based on a total RVU of 1.15 (0.18 work RVU, 0.95 practice expense RVU, 0.02 malpractice RVU) multiplied by the 2025 conversion factor of 32.3465.

Does Medicare still cover mastoid X-rays or are they considered obsolete?

Medicare continues to cover CPT 70120, but coverage is increasingly restricted to specific clinical scenarios where plain films provide adequate diagnostic information. Many Medicare Administrative Contractors (MACs) have Local Coverage Determinations (LCDs) that favor CT imaging for mastoid evaluation, requiring strong medical necessity documentation for plain film authorization, particularly for suspected mastoiditis or complex pathology.

Can I bill CPT 70120 with modifier 50 for bilateral mastoid imaging?

No, you should not append modifier 50 to CPT 70120. The code descriptor 'mastoids' is already plural and encompasses bilateral imaging by default. Using modifier 50 will typically result in claim denial. If only one side is imaged, use modifier RT (right) or LT (left) to specify laterality.

What is the difference between CPT 70120 and temporal bone CT codes?

CPT 70120 is a conventional X-ray examination of the mastoids using plain radiography, while temporal bone CT codes (70480-70482) provide cross-sectional imaging with far superior anatomic detail. CT has largely replaced plain films for mastoid imaging because it better visualizes air cell opacification, bony erosion, and complications. Plain films are now primarily used for initial screening, follow-up of known conditions, or when CT is unavailable.

How do I bill 70120 if I only interpret the images but don't own the equipment?

When you provide only the professional component (interpretation), append modifier 26 to CPT 70120. The facility that owns the equipment and employs the technologist bills for the technical component using modifier TC. The professional component typically represents 40-50% of the total reimbursement, while the technical component represents 50-60%.

What ICD-10 codes support medical necessity for CPT 70120?

Common supporting diagnoses include H70.90 (unspecified mastoiditis), H70.00-H70.93 (acute or chronic mastoiditis variants), H66.90 (otitis media, unspecified), H66.00-H66.93 (various otitis media types), H92.0 (otalgia), R51.9 (headache), and S09.90XA (unspecified injury of head, initial encounter). The diagnosis must clearly support why imaging of the mastoid structures is medically necessary.

Can CPT 70120 be billed on the same day as a CT of the temporal bone?

Generally, no. According to NCCI (National Correct Coding Initiative) edits, when both a mastoid X-ray and temporal bone CT are performed on the same day for the same indication, the plain film is considered bundled into the CT study as it provides redundant information. The CT would be billed instead. Exceptions may exist if the plain film was performed first and the CT was ordered based on plain film findings, but this requires clear documentation of separate medical necessity for each study.