Summary & Overview
CPT 82784: Quantitative Immunoglobulin (Gamma Globulin) Assay
CPT code 82784 represents a quantitative laboratory assay for a specific gamma globulin (IgA, IgD, IgG, or IgM) in biologic specimens such as serum, plasma, cerebrospinal fluid, or other bodily fluids. This technical laboratory service is central to diagnosing and monitoring immune disorders, infectious diseases, and certain neuromuscular or hematologic conditions, making it a commonly ordered clinical chemistry test across inpatient and outpatient settings.
Key payers in the national landscape include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of the clinical context for immunoglobulin quantification, typical sites of service where the technical component is performed, and the payer mix considered in this publication. The report also presents benchmark-oriented content covering utilization patterns and common billing practices, summarizes relevant policy considerations affecting coverage and payment, and clarifies documentation elements typically associated with laboratory services.
This material is intended for healthcare administrators, lab directors, and revenue cycle staff who need a concise reference to the clinical purpose of CPT code 82784, the service setting, and the payer environment affecting laboratory billing and coverage decisions. Data not available in the input will be noted where applicable.
Billing Code Overview
CPT code 82784 describes a laboratory test in which a lab analyst measures the concentration of a specific gamma globulin in a specimen. The test may target immunoglobulin A (IgA), immunoglobulin D (IgD), immunoglobulin G (IgG), or immunoglobulin M (IgM) and is performed on specimens such as serum, plasma, cerebrospinal fluid, or other bodily fluids.
Service Type: Laboratory quantitative immunoglobulin testing (technical component)
Typical Site of Service: Clinical laboratory, hospital laboratory, or other certified diagnostic laboratory facility
Clinical & Coding Specifications
Clinical Context
A 42-year-old patient presents to an outpatient laboratory after referral from an immunology clinic for evaluation of suspected immunodeficiency and chronic recurrent sinusitis. The clinician orders quantitative immunoglobulin testing to measure serum concentrations of immunoglobulin G (IgG), immunoglobulin A (IgA), and immunoglobulin M (IgM) to assess humoral immunity. A phlebotomist collects a serum specimen during a clinic visit; the specimen is sent to the hospital clinical laboratory. A medical laboratory scientist performs the technical assay — for example nephelometry or turbidimetry — to determine the concentration of the requested gamma globulin(s). Results are reported to the ordering provider and used to guide further workup such as specific antibody titers, vaccine response testing, or referral for immunology consultation. Typical sites of service include outpatient laboratories, hospital laboratories, and specialty clinic infusion centers where serum or plasma samples are processed. Specimens may also include cerebrospinal fluid or other body fluids when testing for immunoglobulins in neurologic or rheumatologic evaluations.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing for the physician interpretation component separate from the lab's technical component (rare for automated Ig quantitation). |