TL;DR: CMS modified NCD 155, confirming that sublingual antigen administration is not covered under Medicare, effective March 7, 2026. Here's what billing teams need to know before submitting any antigen-related claims.
The Centers for Medicare & Medicaid Services updated NCD 155, the National Coverage Determination governing Medicare's antigen coverage policy for sublingual administration. The policy is clear and hasn't softened: Medicare does not cover antigens administered by placing drops under the patient's tongue. This applies to services provided on or after November 17, 1996, and the March 7, 2026 revision reaffirms that position without exception. No specific CPT or HCPCS codes are listed in this NCD — we'll get into why that matters for your billing team below.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | CMS (Centers for Medicare & Medicaid Services) |
| Policy | Antigens Prepared for Sublingual Administration |
| Policy Code | NCD 155 |
| Change Type | Modified |
| Effective Date | 2026-03-07 |
| Impact Level | Medium — high risk for claim denial if sublingual delivery is billed |
| Specialties Affected | Allergy/Immunology, ENT, Primary Care billing sublingual immunotherapy |
| Key Action | Audit any antigen claims for delivery route before submission; sublingual administration will not be reimbursed under Medicare |
CMS Antigen Coverage Criteria and Medical Necessity Requirements 2026
The CMS antigen sublingual administration coverage policy is unambiguous. Medicare covers antigens only when they are administered by injection. Sublingual delivery — placing liquid drops under the patient's tongue — does not meet medical necessity under this NCD and has not met it since November 17, 1996.
CMS's stated reason is direct: sublingual antigen therapy has not been proven safe and effective. That's the agency's standard language for a non-covered service, and it carries real weight. When CMS uses that phrase in an NCD, it means no amount of clinical documentation or prior authorization will flip a claim to covered status at the Medicare level.
This is not a gray-zone policy. There's no exception pathway, no coverage with evidence development (CED) track, and no indication-level carve-out. If the route of administration is sublingual, Medicare will not reimburse it. Full stop.
The practical issue for your billing team is the route-of-administration question. Allergy practices often offer both subcutaneous immunotherapy (SCIT) — the injection method — and sublingual immunotherapy (SLIT), which includes both drops and tablets. Medicare covers SCIT. It does not cover SLIT in any form under this NCD. Make sure your charge capture reflects that distinction at the point of documentation, not at the point of claim submission.
Prior authorization doesn't apply here in the traditional sense — there's no authorization pathway for a categorically non-covered service. If your practice is billing Medicare for sublingual antigen therapy and expecting a prior auth to protect you, that's not how this works. A non-covered service is a non-covered service. The authorization process exists for covered services with conditions, not for exclusions.
CMS Antigen Sublingual Administration Exclusions and Non-Covered Indications
The exclusion is both broad and absolute. Any antigen prepared for sublingual administration is excluded from Medicare coverage. The route of delivery — not the antigen itself — is the trigger for non-coverage.
This distinction matters in practice. The antigen formulation used for sublingual delivery may be identical or similar to one used for injection. But once the delivery route is sublingual, NCD 155 applies, and the service is not covered. Your billing guidelines need to capture this at the charge capture level, not just the coding level.
The policy also doesn't distinguish by condition. It doesn't matter whether the patient has allergic rhinitis, asthma, insect venom sensitivity, or food allergies. If the treatment is sublingual antigens, Medicare won't pay. There's no diagnosis code that changes that outcome.
One more point worth making clearly: this NCD is a national determination. Medicare Administrative Contractors (MACs) cannot issue a Local Coverage Determination (LCD) that overrides an NCD. A MAC cannot decide, at the regional level, to cover sublingual antigens if CMS has said no at the national level. Don't rely on MAC-level guidance to create a coverage pathway that doesn't exist.
Coverage Indications at a Glance
| Indication | Status | Relevant Codes | Notes |
|---|---|---|---|
| Antigens administered by injection (subcutaneous) | Covered | Not specified in NCD 155 | Must meet standard medical necessity criteria |
| Antigens administered sublingually (drops under tongue) | Not Covered | Not specified in NCD 155 | Excluded since November 17, 1996; reaffirmed March 7, 2026 |
| Sublingual antigen tablets | Not Covered | Not specified in NCD 155 | Route of administration is sublingual; same exclusion applies |
Note: NCD 155 does not list specific CPT or HCPCS codes. Coverage status is determined by route of administration, not by a code-level designation.
CMS Antigen Sublingual Administration Billing Guidelines and Action Items 2026
The effective date of this revision is March 7, 2026. Here's what your billing team should do now.
| # | Action Item |
|---|---|
| 1 | Audit your charge capture workflow for route-of-administration flags. If your EHR or practice management system doesn't capture "sublingual" vs. "subcutaneous" as a distinct billing field, fix that before submitting any antigen claims to Medicare. A claim denial because of route of administration is 100% preventable. |
| 2 | Pull any pending antigen claims before they go out the door. If you have antigen claims in queue for Medicare patients, verify the delivery route on each one before submission. One sublingual claim that slips through is a denial and a potential overpayment exposure if it somehow paid previously. |
| 3 | Review your patient financial policy and ABN process for SLIT patients. If you offer sublingual immunotherapy to Medicare patients, you need an Advance Beneficiary Notice of Noncoverage (ABN) in place before you deliver the service. Without a valid ABN, you can't bill the patient for a non-covered service. This is where many allergy practices get burned. |
| 4 | Don't bill Medicare for sublingual antigen tablets either. The NCD says "sublingually" — that covers drops and tablets. If you're offering FDA-approved sublingual tablet immunotherapy (like those approved for grass or dust mite allergies), Medicare still won't cover it under NCD 155. That's a separate patient responsibility conversation you need to have upfront. |
| 5 | Brief your clinical and front-desk teams on the coverage policy. Patients often assume Medicare covers everything their doctor recommends. When a physician proposes sublingual immunotherapy for a Medicare patient, the front desk and billing team need to know immediately so they can set expectations, collect an ABN signature, and document the patient's choice to self-pay or decline. |
| 6 | Check whether any secondary payers cover sublingual antigens. Some commercial plans do cover SLIT, including sublingual drops and tablets. If your Medicare patient has a supplement or secondary plan, that plan's coverage policy applies — not NCD 155. Bill the secondary appropriately and document the Medicare non-coverage clearly. |
| 7 | Talk to your compliance officer if your practice has been billing Medicare for sublingual antigens. If you've submitted these claims and received reimbursement, you may have an overpayment issue. Don't assume prior payment means prior approval. NCD 155's exclusion goes back to 1996. Loop in your compliance officer before March 7, 2026, and review your claims history. |
| 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 Antigen Sublingual Administration Under NCD 155
Code Coverage Status
NCD 155 does not list specific CPT, HCPCS Level II, or ICD-10-CM codes. The coverage policy operates at the level of the service description — specifically, the route of administration — rather than at the code level.
This is actually a billing challenge, not a simplification. Without a code-level designation in the NCD, your team can't build a simple "bill this code, don't bill that code" rule. You need a workflow that identifies route of administration before a code is even selected.
What This Means for Antigen Billing
Allergy billing typically involves codes for antigen preparation and injection services. The preparation codes and allergy injection codes that apply to subcutaneous immunotherapy are covered — but only when the delivery is by injection. If your billing team is coding antigen preparation without confirming the delivery route in the clinical documentation, you're flying blind.
Because NCD 155 doesn't enumerate specific codes, coverage decisions for antigen claims are going to hinge on the documentation. The administration note in the clinical record needs to clearly show the route. If the note says "administered sublingually" or "placed under tongue" and you bill Medicare, you'll get a claim denial — or worse, a paid claim that gets clawed back on audit.
Work with your coding team and your MAC to confirm which specific antigen preparation and administration codes you use, and build a route-of-administration checkpoint into your coding workflow. That's the practical fix for a policy that doesn't give you a simple code list.
Get the Full Picture
Track this policy across versions, search 1,500+ policies by CPT code, and get real-time alerts when any payer changes coverage.