Summary & Overview
HCPCS C9133: Factor IX (rixubis), recombinant, per I.U.
HCPCS Level II code C9133 denotes recombinant Factor IX (rixubis), billed per international unit, used for replacement therapy in patients with hemophilia B. This product-level code matters nationally because recombinant clotting factors are high-cost biologics essential for managing bleeding episodes and prophylaxis in this rare but clinically significant condition. Proper coding affects coverage determinations, prior authorization processes, and reimbursement workflows across payers.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context for C9133, typical sites of care where the product is administered, and a summary of what to expect in payer policies and billing practice. The publication provides benchmarks for utilization and cost drivers where available, summaries of common payer policy themes such as medical necessity and prior authorization requirements, and notes on coding considerations specific to high-cost clotting factor products.
The report is intended for billing managers, pharmacy and therapeutics committees, infusion service administrators, and policy analysts seeking a national-level briefing on billing, coverage, and operational issues tied to recombinant Factor IX billed under C9133.
Billing Code Overview
HCPCS Level II code C9133 represents Factor IX (antihemophilic factor, recombinant), rixubis, per international unit (I.U.). This code is used for billing the recombinant clotting factor product rixubis, which is indicated for treatment and control of bleeding in individuals with hemophilia B (factor IX deficiency).
-
Service type: Prescription biologic product for coagulation factor replacement therapy
-
Typical site of service: Infusion services delivered in outpatient infusion centers, hospital outpatient departments, and home infusion settings
Data not available in the input for modifiers, associated taxonomies, ICD-10 diagnoses, related codes, and service line.
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult with hemophilia B presenting for factor replacement therapy following spontaneous joint bleeding, perioperative management, or routine prophylaxis. The patient arrives at an infusion center or hospital outpatient infusion clinic where nursing staff confirm identity, weight, current factor activity levels, and cross-check the prescription for C9133 (Factor IX, recombinant, rixubis, per IU). The clinical workflow includes venous access assessment (peripheral IV or port), reconstitution/aseptic preparation of the recombinant factor IX product by pharmacy or trained infusion staff, dose calculation based on weight and desired international units (IU), verification of allergies and inhibitor status, and administration via IV push or infusion per product labeling. Vital signs are monitored before, during, and after infusion for infusion reactions. For surgical prophylaxis, preoperative dosing is coordinated with the surgical team and hematology. Documentation includes product lot number, units administered (IU), infusion start/stop times, site of service (commonly outpatient infusion center, hospital outpatient department, or physician office), and clinical indication such as acute hemorrhage, perioperative prophylaxis, or routine prophylaxis for severe hemophilia B.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
59 | Distinct Procedural Service | When another service or procedure on the same day is distinct and separate from factor administration (rare for drug-only billing). |