Summary & Overview
HCPCS Level II C9481: Reslizumab Injection, 1 mg
HCPCS Level II code C9481 designates the unit billing for reslizumab at 1 mg per injection. Reslizumab is a biologic monoclonal antibody used in specialist-administered care for certain eosinophilic conditions; coding at the per-milligram level enables precise drug-level billing and claims adjudication. Nationally, accurate use of this HCPCS Level II code matters for drug cost transparency, inventory tracking, and consistent reimbursement for infused or injected biologics provided in outpatient settings.
Key payers in this overview include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the code and its clinical context, typical sites of service, and what to expect in payer coverage patterns. The publication summarizes available benchmarks and billing practice considerations, outlines potential policy updates affecting biologic drug coding and reimbursement, and offers guidance on clinical context relevant to infusion centers and specialty clinics.
This summary is intended for a national audience of billing managers, revenue cycle leaders, and clinical administrators who need to understand how HCPCS Level II code C9481 is used for reslizumab dosing, where it is typically administered, and which major payers are commonly involved in coverage decisions.
Billing Code Overview
HCPCS Level II code C9481 represents Injection, reslizumab, 1 mg. The service is an intravenous or subcutaneous injectable biologic administration of the monoclonal antibody reslizumab measured per milligram. The typical site of service for this administered medication is an outpatient infusion center, hospital outpatient department, or clinic where parenteral biologic therapies are delivered.
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Clinical & Coding Specifications
Clinical Context
A typical patient is an adult with severe eosinophilic asthma inadequately controlled on high-dose inhaled corticosteroids and an additional controller medication, who is evaluated in an outpatient allergy or pulmonary clinic for biologic therapy. The clinician documents persistent symptoms, frequent exacerbations, or reliance on oral corticosteroids and confirms blood eosinophil counts meet criteria for anti-IL-5 therapy. After shared decision-making and baseline screening (including current medications, vaccination status, and review of prior adverse reactions), the patient receives an intravenous infusion of reslizumab prepared by the infusion center pharmacy. The service is billed as C9481 per 1 mg of reslizumab. Typical workflow steps include pre-infusion nursing assessment (vital signs, allergy review), medication verification and dose calculation, IV placement, infusion administration with monitoring for infusion reactions, post-infusion observation (often 30–60 minutes), and documentation of dose, lot number, and patient tolerance. Treatments are commonly scheduled every 4 weeks according to the product dosing regimen, with periodic reassessment of symptoms, exacerbation frequency, and eosinophil counts to document medical necessity for ongoing therapy.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
25 | Significant, separately identifiable evaluation and management service by the same physician on the same day of the procedure |