G9019 Oseltamivir (HCPCS) Reimbursement & Policy

HCPCS Level II code G9019 designates a 75 mg unit of oral oseltamivir phosphate provided under a Medicare-approved demonstration project. The code captures the dispensing of an antiviral agent used for treatment or prophylaxis of influenza within a structured demonstration setting and is relevant where program-specific billing rules apply. Nationally, use of demonstration-specific HCPCS codes like G9019 matters for tracking program participation, ensuring appropriate reimbursement under demonstration rules, and monitoring access to antiviral therapy during targeted initiatives.

Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context and service setting, plus what to expect in associated billing — including where to look for benchmarks and policy updates and how demonstration designations affect claim reporting. The publication outlines the code’s clinical purpose, common sites of service, and the types of information typically required for claims involving demonstration project medications. If specific payer policies, modifiers, taxonomies, or related diagnosis coding are not provided here, the section notes that those details are not available in the input.

Billing Code Overview

HCPCS Level II code G9019 represents oseltamivir phosphate, oral, per 75 mg, designated for use in a Medicare-approved demonstration project. The medication is an oral antiviral agent commonly used to treat and prevent influenza; this HCPCS code documents the dispense of a 75 mg unit within the context of the demonstration.

Service Type: Pharmaceutical dispensing / outpatient oral antiviral therapy

Typical Site of Service: Outpatient clinic, pharmacy, or other outpatient dispensing site

Data not available in the input.

Clinical Context

A 68-year-old Medicare beneficiary presents to a primary care clinic during influenza season with 48 hours of acute onset fever, cough, myalgias, and malaise. The clinician performs a rapid influenza diagnostic test or clinical assessment consistent with uncomplicated influenza A or B and determines antiviral therapy is appropriate under a Medicare-approved demonstration project. The patient receives a single oral dose of antiviral medication dispensed on-site or provided as a take-home supply. Clinical workflow includes evaluation and documentation of symptom onset and eligibility for antiviral treatment, informed consent when required by the demonstration project, medication administration or dispensing, medication counseling regarding dosing and side effects, and documentation of the demonstration project identifier and billing code on the claim.

Coding Specifications

Modifier	Description	When to Use
`25`	Significant, separately identifiable evaluation and management (E/M) service by the same physician on the day of a procedure	Use when a separate E/M visit is performed and documented in addition to administration or dispensing of antiviral therapy.
`59`	Distinct procedural service

Taxonomy Code	Specialty	Notes
`207Q00000X`	Family Medicine	Primary care clinicians who commonly evaluate and treat acute influenza in outpatient settings.
`208D00000X`	General Internal Medicine	Hospital-based or clinic internists providing outpatient antiviral therapy to adult patients.
`207R00000X`	Emergency Medicine	Emergency clinicians who may administer antivirals at ED discharge or as part of outpatient management.
`363LF0000X`	Pharmacy	Pharmacists or clinical pharmacy services involved in dispensing and counseling for antiviral medications.
`208000000X`	Infectious Disease	Specialists consulted for complicated influenza cases or for oversight of demonstration project protocols.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`J09.X1`	Influenza due to certain identified influenza viruses with other respiratory manifestations	Applicable when a specific influenza strain is identified and respiratory symptoms are present, supporting antiviral treatment.
`J10.1`	Influenza due to other identified influenza virus with other respiratory manifestations	Used when influenza virus is identified (e.g., via rapid test) and respiratory involvement supports therapy.
`J11.1`	Influenza, virus not identified, with other respiratory manifestations	Applied when clinical diagnosis of influenza is made without a positive laboratory identification but with respiratory symptoms.
`J11.00`	Influenza, virus not identified, with unspecified type of pneumonia	Used when influenza presents with pneumonia; antiviral therapy may be indicated depending on clinical status.
`Z20.828`	Contact with and (suspected) exposure to other viral communicable diseases	Used for patients with known exposure where post-exposure evaluation and consideration for antiviral prophylaxis may occur.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`99212`	Office or other outpatient visit for the evaluation and management of an established patient, typically 10 minutes	May be billed when a brief E/M visit is performed for influenza evaluation and antiviral prescribing.
`99213`	Office or other outpatient visit for the evaluation and management of an established patient, typically 15 minutes	Commonly billed when a more detailed outpatient evaluation supports antiviral therapy.
`87804`	Infectious agent antigen detection by immunoassay with direct optical observation; influenza	Performed when rapid influenza testing is used to support diagnosis and treatment decisions.
`36591`	Collection of blood specimen from an implantable venous access device; unspecified here but included as an unrelated example	Not typically related; include only when clinical workflow requires blood collection as part of broader evaluation.
`90471`	Immunization administration (includes percutaneous, intradermal, subcutaneous, or intramuscular)	May be used in the same visit if influenza vaccination is also administered; documents separate preventive service.

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Summary & Overview

HCPCS G9019: Oseltamivir phosphate, oral, 75 mg