M1219 Anaphylaxis (HCPCS) Reimbursement & Policy

HCPCS Level II code M1219 identifies anaphylaxis occurring in temporal relation to vaccination, recorded on or before the date of the clinical encounter. Nationally, accurate capture of vaccine-associated anaphylaxis is important for patient safety surveillance, clinical care coordination, and appropriate claims adjudication given the urgent nature of the condition. Typical settings for services billed with this code include emergency departments and urgent care centers where acute allergic reactions are assessed and managed. Key payers included in this overview are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the code's clinical meaning, the service contexts where it is relevant, and the common modifiers used with this code. The brief also outlines what to expect for benchmarking and policy considerations relevant to national billing practice, and highlights areas where input data are not available. Data not available in the input include associated taxonomies, specific ICD-10 diagnosis mappings, and related procedure or service-line detail.

Billing Code Overview

HCPCS Level II code M1219 denotes anaphylaxis due to the vaccine on or before the date of the encounter. This code is used to report the clinical circumstance where a patient experiences anaphylactic reaction temporally associated with a vaccination.

Service type: Emergency evaluation and management or urgent care services related to acute allergic reaction
Typical site of service: Emergency department, urgent care center, or other acute care setting

Data not available in the input for associated taxonomies, ICD-10 diagnoses, and related procedure codes.

Clinical Context

A 28-year-old patient presents to an urgent care clinic within 30 minutes of receiving a routine immunization with sudden onset of generalized hives, facial swelling, bronchospasm with wheeze and shortness of breath, hypotension (systolic blood pressure <90 mmHg), and altered mental status consistent with anaphylaxis due to the vaccine administered earlier that day. The clinical workflow begins with immediate triage and rapid assessment of airway, breathing and circulation, activation of emergency response protocols, administration of intramuscular epinephrine, supplemental oxygen, intravenous access, fluid resuscitation, and adjunctive therapies (antihistamines, corticosteroids, bronchodilators). The encounter is documented as anaphylaxis due to the vaccine on or before the date of the encounter and coded using the HCPCS Level II code M1219. The typical site of service is an urgent care center, emergency department, or outpatient clinic that administers vaccinations. Clinical documentation includes the vaccine given, time of administration, time of symptom onset, vital signs, treatments provided, response to treatment, informed consent for any procedures, and disposition (observation, transfer to higher level of care, or discharge with instructions and emergency kit).

Coding Specifications

Modifier	Description	When to Use
`22`	Increased procedural services	Use when services required substantially greater effort or complexity than usual for management of severe anaphylaxis (must document rationale and report per payer rules).

Taxonomy Code	Specialty	Notes
`208000000X`	Emergency Medicine Physician	Commonly manages acute anaphylaxis, resuscitation, and disposition decisions.
`207P00000X`	Physician Assistant	Provides acute stabilization, medication administration, and documentation in urgent/emergency settings.
`207Q00000X`	Nurse Practitioner	Performs assessment, treatment, and follow-up planning for vaccine-related anaphylaxis.
`363A00000X`	Critical Care Medicine Physician	Consulted for severe or refractory anaphylaxis requiring intensive care and invasive airway management.
`207L00000X`	Anesthesiology Physician	Involved when airway intervention or anesthesia is required for management.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`T78.2XXA`	Anaphylactic shock, unspecified, initial encounter	Common code used for an anaphylactic reaction presenting in the emergency or urgent care setting.
`T80.52XA`	Anaphylactic reaction due to vaccination, initial encounter	Directly specifies anaphylaxis caused by a vaccine and aligns with the HCPCS description for `M1219`.
`T88.1XXA`	Other complications following immunization, initial encounter	Used when complications related to vaccination are documented, including allergic reactions.
`J45.901`	Unspecified asthma with (acute) exacerbation	May be used if anaphylaxis triggers bronchospasm or exacerbation of underlying asthma.
`R07.9`	Chest pain, unspecified	Symptom code that may be reported when patients describe chest tightness during anaphylaxis.
`R42`	Dizziness and giddiness	Symptom code applicable for syncope or presyncope related to hypotension in anaphylaxis.
`I95.9`	Hypotension, unspecified	Applicable when clinically significant hypotension is documented during the anaphylactic event.
`L50.9`	Urticaria, unspecified	Used when hives are a prominent manifestation without coding for systemic anaphylaxis.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`J0170`	Injection, epinephrine, per 0.3 mg (epinephrine supplied in some cases as a billed drug)	Epinephrine administration is first-line treatment for anaphylaxis; drug administration may be billed when not included in facility bundled services.
`31500`	Intubation, endotracheal, emergency procedure	Performed if airway protection is required due to airway edema or respiratory failure from anaphylaxis.
`94010`	Spirometry, spirometric flow/volume graphic study (pre- and post-bronchodilator studies may be used)	Bronchodilator responsiveness assessment or monitoring may be performed during evaluation of bronchospasm in anaphylaxis.
`36000`	Introduction of needle or intracatheter, peripheral vessel, for diagnostic or therapeutic purposes (e.g., IV placement)	Peripheral IV access is established for medication and fluid administration during resuscitation.
`99406`	Smoking and tobacco use cessation counseling visit 3-10 minutes (example of evaluation/management adjunct)	Data not available in the input.

Note: For any code billed, documentation must support medical necessity, time, and services provided in the clinical workflow.

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Summary & Overview

HCPCS Level II M1219: Anaphylaxis Due to Vaccine on or Before Encounter Date