Summary & Overview
HCPCS C9304: Injection, marstacimab-hncq 0.5 mg
HCPCS Level II code C9304 denotes an injection unit of marstacimab-hncq (0.5 mg), a biologic therapeutic administered parenterally. Nationally, distinct HCPCS codes for biologic agents matter for billing accuracy, payer coverage determinations, and tracking utilization of novel therapies. HCPCS-level identifiers support consistent claims adjudication across outpatient infusion centers, clinics, and physician offices.
Key payers examined include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find coverage and coding context useful for claim submission and benefit verification workflows. The publication outlines expected service settings, common modifier considerations, and payer patterns relevant to outpatient biologic administration.
This summary provides clinical and billing context: what the code represents, where it is typically used, and why precise HCPCS reporting is important for reimbursement and utilization monitoring. It also flags where input data is incomplete. The report covers benchmarks and policy context where available, practical coding notes for claims teams, and high-level payer coverage patterns to inform revenue cycle and clinical operations stakeholders about marstacimab-hncq billing under HCPCS Level II code C9304.
Billing Code Overview
HCPCS Level II code C9304 represents the billed supply for an injection of marstacimab-hncq, with a dosing unit of 0.5 mg per code descriptor. The service type associated with this HCPCS Level II code is an injectable biologic/therapeutic administration. The typical site of service for billing this code is outpatient infusion or clinic-based injection administration, where parenteral biologic therapies are commonly delivered.
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Clinical & Coding Specifications
Clinical Context
A typical patient is an adult with a chronic bleeding disorder (for example, hemophilia A with inhibitors or a rare coagulation factor deficiency) who requires subcutaneous administration of a recombinant monoclonal antibody product. The service represented by C9304 (Injection, marstacimab-hncq, 0.5 mg) is delivered in an outpatient infusion/injection clinic, hematology specialty office, or hospital outpatient department. The clinical workflow includes: pre-visit medication reconciliation and assessment of indication and bleeding history; confirmation of weight and dosing schedule; preparation of the single‑dose vial or syringe by pharmacy or trained nursing staff under standard aseptic technique; verification of insurance coverage and applicable prior authorization; administration by a licensed nurse via subcutaneous injection; post‑injection observation for immediate adverse reactions (typically 15–60 minutes depending on patient history); documentation of lot number, dose, route, site, and any immediate reactions; and coordination of follow‑up dosing and home injection training if applicable. Typical patient monitoring includes vital signs, assessment for injection site reactions, bleeding events, and routine laboratory surveillance ordered by the treating hematologist.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
22 | Increased procedural services | When work, time, or intensity for preparation or administration materially exceeds usual expectations for the product injection. |