HCPCS Level II code Q9998 designates the biosimilar formulation of ustekinumab marketed as Selarsdi, billed per 1 mg of product. As a biosimilar billing code for a high-cost biologic, Q9998 matters nationally for drug reimbursement, patient access to biologic therapies, and payer coverage policy development. It affects hospital outpatient departments, infusion centers, and physician practices that administer or procure biologic therapies.

Key payers included in the coverage discussion are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of what the code represents, how it is used in clinical settings, and the typical sites of service. The publication also provides benchmarking context, common billing considerations, and recent policy developments relevant to biosimilar adoption and reimbursement for infused or injected biologics.

The report is intended to help billing managers, revenue cycle leaders, and policy analysts understand where Q9998 fits within pharmacy and medical benefits, what to expect in payer interactions, and which operational areas (procurement, infusion scheduling, claims submission) are most affected. Data not available in the input is noted where applicable.