Summary & Overview

HCPCS C9491: Avelumab Injection, 10 mg

HCPCS Level II code C9491 denotes a 10 mg unit of avelumab administered by injection. Avelumab is an anti–PD-L1 monoclonal antibody used in oncology, and the code standardizes billing for the drug dose rather than the administration procedure. Nationally, accurate coding for high-cost immunotherapy agents like avelumab is important for claims processing, reimbursement clarity, and monitoring utilization of specialty oncology drugs.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of what the code represents, the typical service setting for drug infusion, and the elements commonly reviewed in payer coverage and billing benchmarks. The publication provides context on billing practices for unit-based drug codes, identifies typical places of service for parenteral oncology therapy, and outlines which payer policies and reimbursement topics are most relevant to facilities and billing professionals.

This material is intended for a national audience and focuses on coding clarity, clinical context for the therapy, and the types of benchmarks and policy updates that affect billing for injectable oncologic biologics. Data not available in the input for specific modifiers, taxonomies, ICD-10 pairings, or payer-specific reimbursement rates.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicareC9491HCPCS Level IIavelumaboncologyinjectable biologicdrug billinginfusionparenteral therapy

Billing Code Overview

HCPCS Level II code C9491 represents an injection of avelumab, 10 mg. This code describes the drug administration unit for the monoclonal antibody avelumab measured per 10 mg.

Service type: Drug injection / pharmacologic therapy
Typical site of service: Infusion center, outpatient clinic, or other settings where parenteral oncology drugs are administered

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A typical patient is an adult with a malignancy indicated for treatment with the anti-PD-L1 monoclonal antibody avelumab. The patient presents to an outpatient oncology infusion center for administration of C9491 (Injection, avelumab, 10 mg). The clinical workflow begins with a physician order documenting the indication, dosage, and schedule. A registered nurse performs pre-infusion verification including allergies, vital signs, weight-based dose calculation, review of concomitant medications, and assessment for infusion reaction risk. Baseline laboratory assessments (CBC, comprehensive metabolic panel, thyroid function tests) are reviewed prior to treatment. The pharmacy prepares the weight- or body-surface-area-based dose in an appropriate sterile compounding environment; the dose is labeled and delivered to the infusion suite. The nurse initiates the IV infusion with standard premedication per institutional protocol if indicated, monitors the patient during infusion for signs of infusion-related or immune-mediated adverse events, and documents start and stop times, lot number, and vial/remaining drug disposition. Post-infusion observation is performed per protocol and the provider documents response assessment and any adverse events at follow-up visits. Billing for the drug is reported with C9491 per 10 mg units administered, with appropriate administration CPT codes billed separately by the facility or administering clinician.

Coding Specifications

Modifier	Description	When to Use
`JW`	Drug or biological quantity discarded/not administered to any patient	Use when a portion of a single-use vial of avelumab is wasted and must be reported for tracking; supports documentation of discarded drug quantity.
`Q0`	Investigational clinical service provided in a clinical research study, non-covered	Use when avelumab is administered as part of a clinical trial where services are billed as investigational.
`Q1`	Routine clinical care provided in a clinical research study, covered	Use when avelumab administration in a study is considered routine care and is payable.
`GA`	Waiver of liability statement on file (no ABN)	Use when the provider has a signed Advance Beneficiary Notice for non-covered services when applicable.
`GZ`	Item or service expected to be denied as not reasonable and necessary	Use when the provider anticipates denial for medical necessity for avelumab in a specific indication.
`52`	Reduced services	Use when only part of the usual drug or service is provided (e.g., abbreviated infusion per protocol).
`59`	Distinct procedural service	Use when a separately identifiable service is performed on the same day as the infusion that is not typically included in the administration service.
`25`	Significant, separately identifiable E/M service on the same day	Use when a separate evaluation and management visit is performed by the clinician on the day of infusion.
`24`	Unrelated E/M during a postoperative period	Use when an unrelated E/M is provided within a postoperative global period for a prior procedure.
`76`	Repeat procedure by same physician	Use when the infusion or related procedure is repeated later the same day by the same provider.
`77`	Repeat procedure by another physician	Use when a different physician repeats a procedure later the same day.

Taxonomy Code	Specialty	Notes
`207Q00000X`	Medical Oncology	Primary specialty managing systemic anti-cancer therapy including avelumab.
`207RC0000X`	Hematology/Oncology	Clinicians treating hematologic and solid tumor indications who administer immunotherapy.
`163WL0200X`	Infusion Therapy	Nursing/infusion specialists delivering IV biologic therapies in outpatient infusion centers.
`207V00000X`	Radiation Oncology	Occasionally involved in multidisciplinary care; documents combined modality treatment plans.
`364S00000X`	Nurse Practitioner	Advanced practice providers who may order and manage infusion therapies under protocol.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C43.9`	Malignant melanoma, unspecified	Avelumab may be used for certain metastatic melanoma contexts as an immune checkpoint inhibitor in selected protocols.
`C80.1`	Malignant (primary) neoplasm, unspecified site	Used when a specific primary site is not coded but systemic immunotherapy is given for metastatic disease.
`C76.2`	Malignant neoplasm of retroperitoneum and peritoneum	Representative metastatic sites where systemic immunotherapy like avelumab may be used.
`C34.90`	Malignant neoplasm of unspecified part of bronchus or lung	Avelumab is used in some lung cancer treatment regimens or trials for advanced disease.
`C61`	Malignant neoplasm of prostate	Included as an example of a solid tumor entity where immunotherapy may be considered in select clinical contexts.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`96413`	Chemotherapy administration, IV infusion technique; up to 1 hour, single or initial substance/drug	Commonly billed for the infusion administration time of avelumab when infusion duration is up to 1 hour.
`96415`	Chemotherapy administration, each additional hour (List separately in addition to code for primary infusion)	Billed when the infusion or monitoring time for avelumab extends beyond the initial hour.
`96417`	Chemotherapy administration, each additional sequential infusion up to 1 hour	Used when multiple, sequential infusions are performed during the same session.
`96365`	Intravenous infusion, for therapy, prophylaxis, or diagnosis; initial, up to 1 hour	May be used in some settings for non-chemotherapy biologic infusions if facility policy dictates.
`36415`	Collection of venous blood by venipuncture	Performed prior to infusion for baseline labs and monitoring; billed separately when performed by the facility.
`99070`	Supplies and materials (e.g., saline, tubing) provided by the physician over and above those usually included with the office visit or service	Used to report additional non-standard supplies used during preparation or administration of avelumab.