Summary & Overview
HCPCS Level II C9021: Injection, obinutuzumab, 10 mg
HCPCS Level II code C9021 represents a 10 mg unit of obinutuzumab, a monoclonal antibody used in oncology infusion regimens. As a drug-specific HCPCS Level II code, it is used on outpatient and professional claims to report the supply of obinutuzumab in 10 mg increments and is important for accurate drug charging and utilization tracking in oncology care. Nationally, precise reporting of HCPCS drug codes affects reimbursement, inventory management, and population-level monitoring of biologic usage.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code's clinical context and billing purpose, common sites of service, and which payers use the code in outpatient and physician-administered drug claims. The publication outlines benchmark considerations for unitization of biologic drugs, coding practice implications for infusion centers and oncology clinics, and any recent policy or billing guidance affecting HCPCS drug reporting.
This national summary is designed to help revenue cycle professionals, oncology clinic managers, and policy analysts understand the role of C9021 in claims and how it fits into broader drug coding and reimbursement workflows. Data not available in the input: specific modifier usage, associated taxonomies, ICD-10 diagnoses, related codes, and payer-specific reimbursement rates.
Billing Code Overview
HCPCS Level II code C9021 describes Injection, obinutuzumab, 10 mg. This code denotes the drug product measured in 10 mg units for intravenous or subcutaneous administration as part of oncology infusion therapy.
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Service type: Drug administration for monoclonal antibody therapy
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Typical site of service: Hospital outpatient infusion centers, oncology clinics, and physician office infusion suites
Clinical & Coding Specifications
Clinical Context
A typical patient is a 62-year-old with previously diagnosed follicular lymphoma or chronic lymphocytic leukemia who presents to the outpatient infusion center for a planned dose of obinutuzumab. Prior to treatment, the oncology nurse confirms pre-treatment labs (CBC, renal and hepatic function), reviews prior infusion reactions, and verifies the chemotherapy order and body surface area. An IV access is established and premedications (acetaminophen, an H1-antihistamine, and a corticosteroid) are administered per protocol to reduce infusion-related reactions. The pharmacist prepares C9021 (obinutuzumab, 10 mg) in the appropriate vial concentration and documents lot numbers. During infusion, the nurse monitors vital signs and for signs of infusion reaction; infusion rate is titrated according to tolerance. Post-infusion observation is provided per institutional policy, and electronic medical record documentation includes medication administration record, lot number, dose given, site of service, and any adverse events. Billing for the drug is captured using the HCPCS Level II code C9021 and typically reported by the facility providing the drug in outpatient hospital infusion, physician office (infusion suite), or ambulatory infusion center settings.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
59 | Distinct procedural service | When a separate, unrelated service is performed on the same day as the infusion that would otherwise be bundled |