Summary & Overview
HCPCS J1558: Immune Globulin (Xembify) Injection, 100 mg
HCPCS Level II code J1558 denotes a 100 mg unit of immune globulin (Xembify) administered as an injectable biologic. This product is used in immune deficiency and certain immunomodulatory indications and is billed per 100 mg increment. Nationally, accurate coding for immune globulin products matters because it affects billing precision, inventory tracking, and payer coverage determination for high-cost biologic therapies.
Key payers included in this overview are Aetna, Blue Cross Blue Shield, Cigna, UnitedHealthcare, and Medicare. Readers will find an overview of what the code represents clinically and operationally, typical sites of service, and which payers are relevant for coverage and billing considerations. The publication also outlines benchmarks and policy context where available and highlights common billing themes for injectable biologics, including unitization and site-of-service implications.
This summary is intended for billing administrators, revenue cycle professionals, and clinicians involved in infusion and injection services. Data not available in the input will be noted where applicable in detailed sections.
Billing Code Overview
HCPCS Level II code J1558 represents an injection of immune globulin (Xembify), 100 mg. This code covers administration of the specified immune globulin product formulated for subcutaneous or intravenous use depending on clinical protocol.
Service Type: Injectable biologic therapy
Typical Site of Service: Outpatient infusion or injection setting, including hospital outpatient departments, physician offices, and infusion centers.
Data not available in the input.
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult with primary immunodeficiency or autoimmune-mediated neuropathy requiring replacement or immunomodulatory therapy who presents to an outpatient infusion center or clinic for administration of immune globulin product J1558 (Xembify), billed per 100 mg. The clinical workflow begins with a prior authorization and verification of diagnosis, weight-based dosing calculation, informed consent, and baseline vital signs. An infusion nurse prepares the reconstituted or ready-to-use product, confirms patient identity and allergy history, and starts intravenous or subcutaneous administration per manufacturer and facility protocol. The patient is monitored for infusion-related reactions (vital signs, observation for hypersensitivity), and supportive medications (acetaminophen, antihistamines) are available. Documentation includes medication lot number, dose in mg and total vial units, route, start and stop times, infusion rate changes, observed adverse events, and the applicable billing modifier(s) reflecting payer or clinical circumstances. Typical sites of service are outpatient infusion centers, physician offices, hospital outpatient departments, and home infusion services when appropriate.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier | When no special billing modifier is required |