M1311 HCPCS code: Anaphylaxis due to the vaccine on or before the date of the encounter
M1311 is the HCPCS Level II code for anaphylaxis due to the vaccine on or before the date of the encounter. Its Medicare coverage code is C (Carrier judgment): Coverage is decided by the Medicare contractor (MAC) case by case.
Code details
| Field | Value |
|---|---|
| Section | M codes — Medical services and quality measures |
| Coverage code | C — Carrier judgment |
| Pricing indicator | 00 — Not separately priced by Medicare |
| BETOS category | Z2 |
| Added | 2024-01-01 |
| Last action effective | 2024-01-01 |
What changed for M1311
- 2024-01-01: M1311 added to HCPCS Level II
- Next scheduled CMS quarterly update (HCPCS and DMEPOS fee schedule): 2027-01-01
Frequently asked questions
What is HCPCS code M1311?
M1311 is the HCPCS Level II code for anaphylaxis due to the vaccine on or before the date of the encounter. Short descriptor: "Aphlx to vax bef enc".
Does Medicare cover M1311?
Coverage code C — Carrier judgment. Coverage is decided by the Medicare contractor (MAC) case by case.
Related M13 codes
- M1300 — Influenza immunization was not administered for reasons documented by clinician (e.g., patient allergy or other medical reasons, patient declined or other patient reasons, vaccine not available or other system reasons)
- M1301 — Patient identified as a tobacco user received tobacco cessation intervention during the measurement period or in the six months prior to the measurement period (counseling and/or pharmacotherapy)
- M1302 — Screening, diagnostic, film digital or digital breast tomosynthesis (3d) mammography results documented and reviewed
- M1303 — Hospice services provided to patient any time during the measurement period
- M1304 — Patient did not receive any pneumococcal conjugate or polysaccharide vaccine on or after their 19th birthday and before the end of the measurement period
- M1305 — Patient received any pneumococcal conjugate or polysaccharide vaccine on or after their 19th birthday and before the end of the measurement period
- M1306 — Patient had anaphylaxis due to the pneumococcal vaccine any time during or before the measurement period
- M1307 — Documentation stating the patient has received or is currently receiving palliative or hospice care
- M1308 — Influenza immunization was not administered, reason not given
- M1309 — Palliative care services provided to patient any time during the measurement period
- M1310 — Patient screened for tobacco use and received tobacco cessation intervention during the measurement period or in the six months prior to the measurement period (counseling, pharmacotherapy, or both), if identified as a tobacco user
- M1312 — Patient not screened for tobacco use
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Next steps
- Run a reimbursement report for a device billed under M1311
- Watch M1311 for fee, coverage and descriptor changes
- Build a full Medicare revenue model for M1311
Sources: CMS HCPCS Level II release October 2025; CMS DMEPOS fee schedule; CMS NCCI MUE tables; CMS Medicare utilization (physician and DME supplier files); CMS Medicare Coverage Database articles. Fees are Medicare allowables, not commercial rates. Not billing or legal advice.