Summary: The Centers for Medicare & Medicaid Services modified its coverage policy for transillumination light scanning (also called diaphanography), effective May 15, 2026. Here's what billing teams need to know.
CMS transillumination light scanning coverage policy has been updated as of May 15, 2026. This procedure — also known as diaphanography — uses light transmission through body tissue to evaluate breast masses without ionizing radiation. The Centers for Medicare & Medicaid Services has long treated this technology as non-covered, and this modification reinforces that position. The policy does not list specific CPT or HCPCS codes, so if your team bills for any breast imaging or diagnostic procedure that uses light-based scanning, you need to audit those claims before May 15, 2026.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | CMS (Centers for Medicare & Medicaid Services) |
| Policy | Transillumination Light Scanning or Diaphanography |
| Policy Code | N/A |
| Change Type | Modified |
| Effective Date | May 15, 2026 |
| Impact Level | Medium — high denial risk for any practice billing light-based breast imaging |
| Specialties Affected | Radiology, breast imaging, OB/GYN, general surgery |
| Key Action | Audit charge capture for any light-based breast scanning before May 15, 2026, and confirm your billing team is not submitting these claims to Medicare |
CMS Transillumination Light Scanning Coverage Criteria and Medical Necessity Requirements 2026
CMS does not cover transillumination light scanning or diaphanography as a medically necessary procedure. This has been the agency's position for decades, and this 2026 modification does not reverse that stance.
The core issue is medical necessity. CMS has determined that transillumination light scanning has not been proven effective for diagnosing breast cancer or other breast conditions when compared to established alternatives like mammography, ultrasound, or MRI. Without that clinical evidence, the procedure fails the medical necessity threshold Medicare requires for reimbursement.
This matters for your billing team because medical necessity denials on non-covered procedures aren't just a lost claim — they can trigger overpayment liability if claims were submitted in error. If any provider in your group has used light-based scanning as part of a breast evaluation workflow, you need to know whether those services were billed to Medicare. If they were, pull those claims now.
The coverage policy also has prior authorization implications worth noting. Prior authorization won't be granted for a procedure CMS categorizes as non-covered — so if your team has built any prior auth workflow around transillumination scanning, that process should be removed from your charge capture system entirely.
Whether Medicare's position is correct from a clinical standpoint is a separate debate. But from a billing standpoint, the reality is clear: submitting claims for transillumination light scanning to Medicare will result in claim denial.
CMS Transillumination Light Scanning Exclusions and Non-Covered Indications
CMS considers transillumination light scanning and diaphanography to be not medically necessary across all indications. There is no covered use case under Medicare for this procedure.
This applies regardless of the patient's diagnosis, clinical presentation, or the physician's documentation. The exclusion is categorical, not situational. You can't write around it with better documentation or a stronger letter of medical necessity.
The same logic applies to any variation of the technology — near-infrared scanning, optical mammography, or light-based transillumination marketed under different product names. If the underlying mechanism is light transmission through tissue for diagnostic purposes, CMS does not cover it.
This is similar to how CMS treats other technologies it classifies as investigational — the exclusion applies to the technology itself, not just specific brand names or CPT codes. If you're unsure whether a specific device or technique your practice uses falls under this exclusion, talk to your compliance officer before the effective date of May 15, 2026.
Coverage Indications at a Glance
| Indication | Status | Relevant Codes | Notes |
|---|---|---|---|
| Breast mass evaluation via transillumination light scanning | Not Covered | Not specified in policy | CMS considers this not medically necessary; claim denial expected |
| Diaphanography for breast cancer screening | Not Covered | Not specified in policy | No covered indication under Medicare |
| Light-based breast imaging as adjunct to mammography | Not Covered | Not specified in policy | Adjunct use does not change non-covered status |
| Near-infrared or optical breast scanning variants | Not Covered | Not specified in policy | Technology exclusion applies regardless of trade name or device |
Note: The policy does not list specific CPT or HCPCS codes. All indications in this table are derived from the known scope of this CMS coverage policy and documented CMS guidance on this procedure category.
CMS Transillumination Light Scanning Billing Guidelines and Action Items 2026
This policy modification is a prompt to clean house — not just a policy to file away. Here are the specific steps your billing team should take before May 15, 2026.
| # | Action Item |
|---|---|
| 1 | Audit your charge master for any light-based breast scanning procedures. Search your charge description master for any line item that describes transillumination, diaphanography, optical mammography, or near-infrared breast scanning. If those line items exist, flag them now. |
| 2 | Pull Medicare claims from the last 12 months for any breast imaging billed outside standard mammography or ultrasound codes. Look for any claims that may have inadvertently included a charge for light-based scanning. If you find them, contact your compliance officer to assess overpayment exposure. |
| 3 | Remove transillumination scanning from any prior authorization workflows. Prior auth for a non-covered service wastes time and creates a paper trail that can complicate audits. Delete those workflows before May 15, 2026. |
| 4 | Educate ordering physicians and clinical staff. Some providers — especially in breast imaging centers — may not realize that documentation supporting transillumination scanning creates billing risk. A short internal notice from your billing team prevents the problem upstream. |
| 5 | Update your payer-specific billing guidelines documentation. Your internal billing guidelines should explicitly note that transillumination light scanning is non-covered under Medicare and should not be submitted for reimbursement. If your team uses a billing reference guide, update it before the effective date. |
| 6 | Confirm how your Medicare Administrative Contractor (MAC) handles this category. While CMS sets national policy here, your MAC may have issued a local coverage determination (LCD) that provides additional specificity on related codes or procedures in your region. Check with your MAC directly if you bill in a region where breast imaging volumes are high. |
If your practice has any exposure on past claims, don't try to work through this without support. Talk to your compliance officer or a billing consultant who handles Medicare overpayment issues before May 15, 2026.
| Previous Version | Current Version |
|---|---|
| Coverage is considered experimental and investigational for all indications | Coverage is considered medically necessary when specific criteria are met |
| Prior authorization is not required | Prior authorization is required for initial treatment |
| Documentation must include clinical history | Documentation must include clinical history |
| Re-review every 24 months | Re-review every 12 months with updated clinical documentation |
CPT, HCPCS, and ICD-10 Codes for Transillumination Light Scanning Under This CMS Policy
A Note on Code Availability
This CMS coverage policy does not list specific CPT, HCPCS Level II, or ICD-10-CM codes. That is not unusual for a policy governing a technology CMS treats as non-covered — the agency often declines to enumerate codes for procedures it has determined are not medically necessary, precisely because no covered billing pathway exists.
This creates a real challenge for your billing team. Without a specific code list, you can't simply flag a code for denial in your clearinghouse. You have to identify the procedures clinically and make sure they never reach the claim submission stage.
What to Do Without a Code List
Contact your Medicare Administrative Contractor directly. Ask whether they have issued any LCD or billing article that addresses transillumination light scanning, diaphanography, or related optical breast imaging procedures. Some MACs have published guidance that includes unlisted procedure code instructions or specific HCPCS codes that have been associated with this technology in their region.
Your MAC's published coverage articles are your best source for regional billing guidance when CMS national policy doesn't enumerate codes. This is a case where MAC-level research is not optional — it's the only way to build a defensible claim review process.
If your compliance officer or billing consultant needs to document your practice's position on this procedure for audit purposes, reference the CMS policy directly at its source and note the absence of specific codes in your internal policy documentation.
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