Summary & Overview

CPT 90371: Hepatitis B Immunoglobulin (HBIg)

CPT code 90371 represents hepatitis B immunoglobulin (HBIg), a plasma‑derived immune globulin product used to provide passive immunity against hepatitis B virus. Nationally, this code is important for post‑exposure prophylaxis, protection of high‑risk individuals, and management of perinatal exposure scenarios. Use of HBIg can reduce acute infection and transmission risk, making correct coding and billing critical for hospitals, outpatient clinics, and infusion centers.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context and administration settings, billing and coding considerations, and payer coverage patterns. The report summarizes available benchmarks where present, highlights common coding modifiers and service‑line placement, and outlines operational implications for clinicians and billing teams.

This publication provides practical, national‑level information on CPT code 90371 to support accurate claim submission, clinical documentation alignment, and payer communication. Data not available in the input is noted where relevant.

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Billing Code Overview

CPT code 90371 describes hepatitis B immunoglobulin (HBIg), a pooled human plasma–derived immunoglobulin with high titers of anti–HBs used to provide passive immunity against hepatitis B. The product is an immune globulin preparation intended to confer immediate, short-term protection following exposure or for individuals at high risk of hepatitis B infection.

Service type: Administration of a plasma-derived immunoglobulin product for passive immunization
Typical site of service: Outpatient clinics, hospital outpatient departments, emergency departments, or infusion centers where immunoglobulin products are administered

Clinical & Coding Specifications

Clinical Context

A 34-year-old patient with recent occupational exposure to a known HBsAg-positive source presents to the outpatient occupational health clinic within 14 days of a needlestick injury. The clinician documents the exposure, reviews the patients vaccination history, and orders hepatitis B surface antibody testing. Because the patient is not immune and needs immediate passive protection, hepatitis B immune globulin (HBIg) is administered intramuscularly during the visit. The visit includes pre-administration counseling, informed consent, verification of lot and expiration of 90371 product, administration by a registered nurse, observation for 15–30 minutes for adverse reaction, and documentation of the dose, route, site, lot number, and patient response in the medical record.

Coding Specifications

Modifier	Description	When to Use
`25`	Significant, separately identifiable evaluation and management service by the same physician on the same day of the procedure	Use when a distinct E/M visit occurs on the same day as `90371` (Note: `25` is not in the provided modifier list; follow provided list only).
`26`	Professional component	Use when reporting only the professional component of a service related to administration oversight (rare for `90371`).
`52`	Reduced services	Use when the full dose or service is partially reduced or not fully rendered.
`53`	Discontinued procedure	Use if administration was started but discontinued due to patient reaction or other urgent reason.
`55`	Postoperative management only	Not typically used for `90371`; avoid unless reporting postoperative care separate from the immunoglobulin service.
`62`	Two surgeons	Not applicable to routine intramuscular `90371` administration; select only if two qualified clinicians are involved in a complex setting.
`78`	Unplanned return to the operating/procedure room by the same physician following initial procedure for a related procedure during the postoperative period	Not typical for `90371`; reserved for procedural returns.
`80`	Assistant surgeon	Not applicable for routine outpatient `90371` injections.
`JW`	Drug or biological agent that has been discarded/not administered to any patient	Use when a portion or entire vial of HBIg is discarded and not administered.
`JZ`	Dose or quantity of a drug not administered to the patient	Use when documented that a specific portion of the prepared dose was not given.

Taxonomy Code	Specialty	Notes
207RC0000X	Internal Medicine	Occupational health and adult immunization management.
208000000X	Emergency Medicine	ED frequently manages acute exposures and administers HBIg.
3336C0003X	Occupational Medicine	Primary specialty for workplace exposure evaluation and prophylaxis.
363L00000X	Infectious Disease	Consult for complex post-exposure prophylaxis decisions.
164W00000X	Family Medicine	Commonly administers immunizations and HBIg in clinic settings.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`Z20.828`	Contact with and (suspected) exposure to other viral communicable diseases	Common code for documented exposure to hepatitis B where post-exposure prophylaxis is given.
`Z23`	Encounter for immunization	Used when the primary purpose of the visit is administration of an immunization or passive immunization like HBIg.
`B16.9`	Acute hepatitis B without delta-agent, without hepatic coma	Relevant when HBIg is given for recent known-source exposures or household contacts of acute cases.
`Z29.2`	Need for prophylactic vaccination and inoculation against single bacterial diseases (used for prophylaxis)	Used in some settings to indicate prophylactic passive immunization; select appropriate prophylaxis code per payer guidelines.
`T81.4XXA`	Infection following a procedure, initial encounter	Relevant if HBIg is given in the context of a procedure-related exposure or complication.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`96372`	Therapeutic, prophylactic, or diagnostic injection (specify substance or drug); subcutaneous or intramuscular	Used for administration of injections in outpatient settings; sometimes reported when facility or payer prefers injection administration code instead of specific biologic code.
`90460`	Immunization administration through 18 years of age via any route of administration; first or only component of each vaccine or toxoid administered	Not directly applicable for adult HBIg but related to immunization administration reporting workflows.
`90471`	Immunization administration (includes percutaneous, intradermal, subcutaneous, or intramuscular) single or initial vaccine/toxoid	Used to report the administration service when payers require separate administration code alongside the biologic.
`86621`	Hepatitis B surface antibody (anti-HBs)	Laboratory test commonly ordered before or after HBIg to assess immunity or response.
`80081`	Hepatic function panel	Often ordered to evaluate baseline liver status in cases of hepatitis exposure.