HCPCS Code Q5123: Injection, Rituximab-arrx, Biosimilar, (Riabni), 10 mg

## **HCPCS code Q5123 documentation requirements** The documentation requirements for HCPCS code Q5123 (Injection, rituximab-arrx, biosimilar, Riabni 10 mg) include: - Report HCPCS code Q5123 with a detailed description and use the JW modifier on Medicare Part B claims to note any drug amount discarded or not administered to the patient. - Documentation should include the appropriate diagnosis codes (ICD-10) corresponding to the patient’s diagnosis, such as B-cell lymphoma, T-cell lymphoma, large B-cell lymphoma, immune thrombocytopenic purpura, or rapidly progressive nephritic syndrome. - If NDC reporting is required (e.g., Medicaid or some commercial payers), the NDC information for Riabni must be included in the claim. - The infusion or administration of the drug should be reported using the appropriate drug administration CPT codes as per payer or Medicare contractor guidance. - Medicare requires compliance with its usual documentation rules for detailed coding and claim submission, including proper modifiers and diagnosis linkage. - Documentation should support the medical necessity, including a face-to-face encounter with the patient and clinician, as well as a valid written order prior to delivery, where applicable. - Providers should maintain documentation of the drug administration, including quantities and dosages, noting any discarded amounts using the JW modifier. - Follow payer-specific instructions for revenue codes related to drug billing (example, Medicare uses revenue code 0636 for drugs requiring detailed coding).

## **HCPCS code Q5123 billing requirements** The billing requirements for HCPCS code Q5123 (Injection, rituximab-arrx, biosimilar, Riabni 10 mg) include the following key points: - Medicare requires reporting HCPCS code Q5123 for the specific biosimilar drug Rituximab-arrx (Riabni), in addition to other biosimilars like rituximab-pvvr and rituximab-arrx. - The JW modifier must be used on Medicare Part B claims to report any drug amount discarded or not administered to the patient (as Q5123 is a drug in a single-use container). - The associated drug administration procedure must be reported separately using the appropriate CPT drug administration codes based on the payer or Medicare contractor guidelines. - Reports should include relevant ICD-10 diagnosis codes that justify the medical necessity of administering the drug, including rheumatoid factor–related conditions, lung involvement, or central nervous system disorders classified under immune diseases. - For claims under the 340B Drug Pricing Program, modifiers such as "JG" or "TB" must be used when applicable, per CMS requirements from 2023 onward. - Medicare uses revenue code 0636 for detailed drug coding, and other payers may use code 0250 or 0636 depending on their policies. - Claims must reflect the accurate number of single-dose vials used, usually reported via NDC in specific claim form fields when required by Medicaid or commercial payers. - The national average Medicare reimbursement rate for Q5123 in 2025 is around $44.23, but rates vary by payer, geography, and provider contracts. - Documentation and billing must comply with CMS guidelines and regional Medicare Administrative Contractor (MAC) instructions to avoid claim denials.

## **Other relevant codes** Other relevant HCPCS codes related to HCPCS Q5123 (Injection, rituximab-arrx, biosimilar, Riabni 10 mg) include codes for other rituximab biosimilars and related biologic drugs: - Q5115: Injection, rituximab-abbs, biosimilar, 10 mg (Truxima) - Q5119: Injection, rituximab-pvvr, biosimilar, 10 mg (Ruxience) - J9312: Injection, rituximab, 10 mg (reference rituximab drug) - J9311: Injection, rituximab 10 mg and hyaluronidase (combination product) - J3590: Unclassified biologics (used sometimes for unspecified biologics) - Q5122: Injection, pegfilgrastim-apgf, biosimilar, 0.5 mg - Q5124: Injection, ranibizumab-nuna, biosimilar, 0.1 mg