HCPCS Level II code J1304 denotes a per-milligram billing unit for tofersen, an injectable specialty medication used in neurology. The code is used when billing the pharmaceutical product itself and is relevant for facilities and clinicians that provide specialty drug administration in outpatient infusion centers, hospital outpatient departments, and physician offices. Nationally, accurate coding for high-cost specialty injectables like tofersen matters for payer coverage determinations, prior authorization workflows, and claims adjudication.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of code definition and clinical context, descriptions of typical sites of service, and guidance on which stakeholders commonly engage with this code. The publication outlines typical billing considerations for a specialty injectable product unit code, summarizes common modifier usage provided in the input, and indicates where input data is missing.

This resource is intended to inform revenue cycle professionals, pharmacy and therapeutics staff, and clinicians involved in specialty drug delivery about the billing identity of tofersen at a national level, and what to expect when preparing claims and interacting with major payers.