TL;DR: The Centers for Medicare & Medicaid Services modified NCD 149, its national coverage determination for Dimethyl Sulfoxide (DMSO), effective March 7, 2026. Here's what changes for billing teams.
The CMS DMSO coverage policy under NCD 149 Medicare is narrower than many billing teams assume. The Centers for Medicare & Medicaid Services covers DMSO for exactly one indication: the treatment of interstitial cystitis. Bill it for anything else and you're looking at a claim denial. This policy doesn't list specific CPT or HCPCS codes — which creates its own set of documentation challenges for your billing team.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | CMS (Centers for Medicare & Medicaid Services) |
| Policy | Dimethyl Sulfoxide (DMSO) — NCD 149 |
| Policy Code | NCD 149 |
| Change Type | Modified |
| Effective Date | 2026-03-07 |
| Impact Level | Medium |
| Specialties Affected | Urology, Infusion Therapy, Pain Management |
| Key Action | Confirm every DMSO claim is documented for interstitial cystitis before billing Medicare |
CMS DMSO Coverage Criteria and Medical Necessity Requirements 2026
The FDA has one approved human use for DMSO: treating interstitial cystitis. CMS follows that determination exactly. The coverage policy states that DMSO is only considered reasonable and necessary for patients being treated for interstitial cystitis. That's the entire covered universe.
Medical necessity here isn't open to interpretation. If the diagnosis isn't interstitial cystitis, Medicare will not reimburse the claim. Your documentation needs to reflect that diagnosis clearly and directly — not as a secondary mention buried in the chart.
This is a binary coverage policy. Covered or not covered. There's no middle ground with tiered criteria, step therapy requirements, or documentation thresholds beyond confirming the diagnosis. That simplicity is useful, but it also means there's no flexibility when you're working with a diagnosis that's adjacent to interstitial cystitis but not the condition itself.
Prior authorization isn't specifically called out in NCD 149 for DMSO. That doesn't mean your MAC won't have additional requirements. Check your local coverage determination rules before assuming a clean prior auth path. Some Medicare Administrative Contractors layer additional documentation requirements on top of NCDs, and DMSO is exactly the kind of drug where that happens.
The medical necessity standard here ties directly to FDA determination, not just clinical judgment. CMS is explicit: the FDA found DMSO safe and effective for humans only in the context of interstitial cystitis treatment. That FDA finding is the anchor for every coverage decision under this policy. If a provider wants to use DMSO off-label, Medicare won't pay — regardless of the clinical rationale in the chart.
CMS DMSO Exclusions and Non-Covered Indications
This is where billing teams get burned. DMSO has a long history of off-label use. Practitioners use it for pain management, wound care, inflammation, and as a carrier agent for other drugs. None of those indications are covered under Medicare.
The language in NCD 149 is unambiguous. Use of DMSO for all indications other than interstitial cystitis is not considered reasonable and necessary. Full stop. CMS doesn't list the excluded indications because it doesn't need to — everything outside of interstitial cystitis is excluded by default.
The real issue here is that DMSO billing often shows up in contexts where the interstitial cystitis diagnosis is secondary or poorly documented. Pain management clinics and infusion centers are particularly exposed. If your team is processing DMSO claims from those settings, audit the diagnosis codes on those claims now — before March 7, 2026.
This also means you can't bill DMSO as a component of a treatment protocol where the primary goal isn't interstitial cystitis management. Using DMSO as a vehicle or adjuvant in another therapy doesn't bring that use under coverage. CMS covers the indication, not the ingredient.
Coverage Indications at a Glance
| Indication | Status | Relevant Codes | Notes |
|---|---|---|---|
| Interstitial cystitis treatment | Covered | No specific codes listed in NCD 149 | Must be documented as primary or clear treatment indication; FDA-approved use |
| Pain management | Not Covered | N/A | Off-label use; not considered reasonable and necessary under Medicare |
| Wound care / topical anti-inflammatory | Not Covered | N/A | Off-label use; excluded by policy |
| Use as a drug carrier/adjuvant | Not Covered | N/A | Indication-based coverage only; adjuvant use not covered |
| All other indications | Not Covered | N/A | Any use outside interstitial cystitis fails medical necessity under NCD 149 |
CMS DMSO Billing Guidelines and Action Items 2026
NCD 149 is straightforward on paper. The billing execution is where teams run into trouble. Here are the steps your team should take before and after the effective date of March 7, 2026.
| # | Action Item |
|---|---|
| 1 | Audit open and recent DMSO claims now. Pull every DMSO claim submitted in the last 12 months. Confirm each one carries a documented interstitial cystitis diagnosis. Flag any claim where the diagnosis is missing, secondary, or off-label. If those claims haven't been adjudicated yet, you have time to correct them. |
| 2 | Check your MAC's local coverage determination. NCD 149 sets the national floor. Your Medicare Administrative Contractor may have an LCD that adds documentation or prior authorization requirements on top. Look this up by MAC region before assuming the NCD is the only rule in play. |
| 3 | Update your charge capture workflow for DMSO billing. Build a hard stop into your charge capture or billing software that requires a confirmed interstitial cystitis diagnosis before a DMSO claim can move forward. This prevents off-label claims from slipping through during high-volume billing cycles. |
| 4 | Verify diagnosis code placement on DMSO claims. The interstitial cystitis diagnosis needs to be clearly connected to the DMSO administration. Diagnosis codes should be specific. If you're uncertain which ICD-10-CM codes your MAC expects, contact them directly — NCD 149 doesn't list specific codes, which means your MAC's guidance carries extra weight here. |
| 5 | Train your infusion and pain management billing staff specifically. These are the two settings most likely to generate DMSO claims with non-covered indications. Run a short internal training before March 7, 2026 that covers what's covered, what's not, and what documentation is required. Don't assume this is common knowledge — it isn't. |
| 6 | Document medical necessity at the point of service, not after the fact. The chart note needs to show that DMSO was administered specifically for interstitial cystitis. Retrospective documentation doesn't hold up in a Medicare audit. The treating provider's note should use clinical language consistent with an interstitial cystitis diagnosis. |
| 7 | Talk to your compliance officer if you're unsure about existing claims. If your practice has been billing DMSO for anything other than interstitial cystitis — even occasionally — loop in your compliance officer before the effective date. You may need to assess overpayment exposure and consider voluntary repayment. Don't wait for a RAC audit to surface the issue. |
| 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 DMSO Under NCD 149
This is where NCD 149 creates a real operational gap. The policy does not list specific CPT, HCPCS, or ICD-10 codes. That's not an oversight on our part — the policy genuinely contains no code-level detail.
Covered CPT/HCPCS Codes
| Code | Type | Description |
|---|---|---|
| Not specified in NCD 149 | — | CMS does not list specific CPT or HCPCS codes in this policy. Contact your MAC for code-level billing guidance. |
Key ICD-10-CM Diagnosis Codes
| Code | Description |
|---|---|
| Not specified in NCD 149 | CMS does not list specific ICD-10-CM codes in this policy. The covered indication is interstitial cystitis — work with your MAC or coding team to confirm the appropriate ICD-10-CM codes for your claims. |
The absence of specific codes in this policy puts more weight on your coding team's judgment and your MAC's guidance. This is not typical for an NCD. Most national coverage determinations include at least some code-level structure. The lack of codes here means your billing team needs to be more deliberate — not less — about how DMSO claims are coded and documented.
If you're billing DMSO regularly, get written guidance from your MAC. That documentation protects you if a claim is later questioned. Don't rely on verbal guidance or assumptions about what codes are appropriate.
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