Summary: The Centers for Medicare & Medicaid Services modified its coverage policy for oxygen treatment of inner ear conditions and carbon therapy, effective May 15, 2026. Here's what billing teams need to know before claims start hitting the system.
CMS oxygen and carbon therapy coverage policy changes don't get a lot of attention — until your claims start denying. This modification affects how Medicare processes reimbursement for hyperbaric-adjacent and inner ear oxygen treatments. The policy does not list specific CPT or HCPCS codes in the available documentation, which is itself a problem we'll address below. If you bill for hyperbaric oxygen therapy, inner ear treatments, or related services for Medicare patients, read this before May 15, 2026.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | Centers for Medicare & Medicaid Services (CMS) |
| Policy | Oxygen Treatment of Inner Ear / Carbon Therapy |
| Policy Code | N/A |
| Change Type | Modified |
| Effective Date | May 15, 2026 |
| Impact Level | Medium-High |
| Specialties Affected | Otolaryngology, Hyperbaric Medicine, Neurology, Audiology, DME suppliers |
| Key Action | Audit your charge capture and medical necessity documentation for inner ear oxygen and carbon therapy claims before May 15, 2026 |
CMS Oxygen Treatment of Inner Ear and Carbon Therapy Coverage Criteria and Medical Necessity Requirements 2026
The core issue with this policy is also the most frustrating thing about it: the available CMS documentation does not list specific CPT or HCPCS codes. That's not an oversight on our end — that's a real gap you need to flag for your billing team right now.
What we do know is that this is a modification to an existing coverage policy. CMS doesn't modify policies without a reason. Changes to coverage designations for oxygen-based therapies typically mean one of two things: criteria tightened, or an experimental designation got added. Either way, your claims are at risk if your documentation doesn't match the updated standard.
Oxygen treatment for inner ear conditions — including conditions like sudden sensorineural hearing loss — has historically lived in a gray zone under Medicare. Some Medicare Administrative Contractors have covered it under hyperbaric oxygen NCD guidelines. Others have issued Local Coverage Determinations restricting it. This CMS modification may be an attempt to standardize that patchwork, or it may push certain indications firmly into the "not covered" column.
Carbon therapy is where this gets even more complicated. Carbon therapy — including carbon dioxide therapy and related inhalation-based treatments — has a limited Medicare coverage history. CMS has treated various forms of this therapy as experimental or investigational at different points. If your practice offers any carbon-based inhalation or topical therapy, your compliance officer needs to review this policy modification before the effective date of May 15, 2026.
Medical necessity documentation is your first line of defense against a claim denial here. Whatever the updated criteria require, you need physician documentation that maps directly to the covered indications. Vague notes about "inner ear dysfunction" won't hold up. You need the diagnosis, the treatment rationale, and the clinical evidence tied to the specific condition CMS recognizes.
Prior authorization requirements for these services vary by MAC region. Check with your local Medicare Administrative Contractor to confirm whether prior authorization applies to the specific codes you're billing. Don't assume the pre-modification rules still apply after May 15, 2026.
CMS Oxygen Treatment of Inner Ear and Carbon Therapy Exclusions and Non-Covered Indications
This is where billing teams get caught off guard. CMS has a long history of designating oxygen-based and carbon-based therapies as experimental or investigational when used outside tightly defined indications.
Chronic inner ear oxygen therapy — meaning ongoing, maintenance-use oxygen treatment for chronic hearing loss or tinnitus — is the type of indication most likely to fall outside covered status. Medicare's general rule is that treatments for chronic, stable conditions don't qualify unless there's a defined therapeutic endpoint and documented medical necessity for each course of treatment.
Carbon therapy for cosmetic or wellness indications will not be covered. Full stop. If anyone in your practice is billing Medicare for carbon dioxide facials, carboxytherapy for non-wound indications, or any form of carbon treatment without a clear medical diagnosis, stop those claims now.
The real exposure here is in the gray middle: treatments that have some clinical evidence, some physician support, and some MAC coverage — but where this CMS modification may now draw a hard line. If you're in that gray zone, get a coverage opinion from your MAC before May 15, 2026.
Coverage Indications at a Glance
Because the policy documentation does not provide specific code-level coverage determinations, this table reflects CMS's known historical positions and the implications of a modification to this policy type. Confirm each indication against the final published policy text before billing.
| Indication | Status | Relevant Codes | Notes |
|---|---|---|---|
| Sudden sensorineural hearing loss — acute, hyperbaric oxygen treatment | Likely Covered (when criteria met) | Not listed in policy data | Requires documented acute onset, failed conventional treatment; confirm with MAC LCD |
| Chronic inner ear oxygen therapy for stable hearing loss | Likely Not Covered | Not listed in policy data | CMS historically excludes maintenance therapy without acute indication |
| Carbon therapy for wound healing / chronic wound indications | Status Uncertain — verify with MAC | Not listed in policy data | May require prior auth; local coverage determination may apply |
| Carbon therapy for cosmetic or wellness purposes | Not Covered | Not listed in policy data | No Medicare coverage for non-medical indications |
| Hyperbaric oxygen therapy for FDA-approved indications | Covered separately under existing NCD | See existing HBO NCD | This policy modification may clarify overlap with inner ear indications |
| Experimental or investigational carbon therapy protocols | Not Covered / Experimental | Not listed in policy data | CMS modification may expand experimental designation — verify before billing |
Important: This table is based on CMS's established coverage history and the policy title. The policy data provided does not include specific codes or indication-level criteria. Pull the full policy text from CMS before using this table for billing decisions.
CMS Oxygen and Carbon Therapy Billing Guidelines and Action Items 2026
These are the steps your billing team needs to take before May 15, 2026. Not suggestions — steps.
| # | Action Item |
|---|---|
| 1 | Pull the full policy text from CMS. The available documentation does not list specific CPT or HCPCS codes. Go to the CMS website and find the complete policy document. Your billing guidelines cannot be updated until you have the actual code list and criteria language. |
| 2 | Contact your Medicare Administrative Contractor before May 15, 2026. Inner ear oxygen treatment reimbursement has historically varied by MAC region. Ask your MAC whether a Local Coverage Determination exists for these services, whether prior authorization is required, and how the CMS modification interacts with any existing LCD. |
| 3 | Audit open and pending claims for inner ear oxygen and carbon therapy. Pull any claims filed in the 90 days before May 15, 2026 that touch these service categories. If the criteria shifted, claims that were compliant under the old policy may not be compliant under the new one. Don't wait for a denial to find out. |
| 4 | Update your medical necessity templates now. Work with your clinical staff to make sure documentation for inner ear oxygen treatments includes: diagnosis code, onset date, prior treatments attempted, and the clinical rationale for this course of therapy. Generic documentation is the fastest path to a claim denial. |
| 5 | Flag carbon therapy claims for compliance review. If your practice offers any form of carbon-based therapy to Medicare patients, have your compliance officer review each indication against the updated coverage policy. Carbon therapy billing is a high-risk area. If you're not sure how this applies to your service mix, loop in your compliance officer before the effective date. |
| 6 | Set a review date 30 days post-effective. Schedule a claims review for mid-June 2026. Look at denial rates for these service categories specifically. If denials spike after May 15, 2026, you want to catch that pattern early and appeal with the correct documentation — not three months later. |
| 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 Oxygen Treatment of Inner Ear / Carbon Therapy
No Specific Codes Listed in Policy Data
The CMS policy document for this modification does not provide a code list in the available data. This is a significant gap for your billing team.
Do not use codes from other sources and assume they apply to this policy. The codes that apply to CMS oxygen treatment of inner ear and carbon therapy billing need to come from the actual policy text or from your MAC's LCD if one exists.
What to Do Instead
| Step | Action |
|---|---|
| 1. Access the full CMS policy | Visit app.payerpolicy.org/p/cms/43-v1 for the source document |
| 2. Check for an NCD | Search the CMS NCD database for hyperbaric oxygen and inner ear oxygen indications — existing NCDs may contain the applicable HCPCS codes |
| 3. Check your MAC's LCD | Search your MAC's LCD database for local coverage determinations on hyperbaric oxygen, inner ear treatment, and carbon therapy |
| 4. Contact your MAC directly | Call your MAC's provider services line to confirm which codes they accept for these services under the updated policy |
Known Adjacent Codes to Verify (Do Not Bill Without Confirming)
These are codes historically associated with this treatment category. Confirm against the actual policy text before use. This blog post does not confirm these as covered — we are flagging them for your verification only.
- Hyperbaric oxygen therapy codes (HCPCS A-series) — check NCD alignment
- Otolaryngology evaluation and management codes — confirm diagnosis code requirements
- Any applicable audiology CPT codes — confirm coverage status under this modification
Your MAC and the full policy text are the authoritative sources here. Don't file claims based on assumptions.
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