Summary & Overview
CPT 86778: Toxoplasma IgM Antibody Immunoassay
CPT code 86778 denotes an immunoassay to detect IgM antibodies to Toxoplasma in serum or cerebrospinal fluid, indicating current toxoplasmosis infection. This laboratory test is clinically important for diagnosing acute or recently acquired infection, guiding clinical management in immunocompetent and immunocompromised patients, and informing public health surveillance for congenital and acquired disease. Nationwide, laboratory reporting and payer coverage for infectious serology affect access to timely diagnosis and treatment.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise review of clinical context, typical sites of service, and common billing considerations. The publication summarizes benchmarks where available, outlines relevant coverage themes across major payers, and highlights policy or administrative updates that affect laboratory testing and claims processing. Clinical implications, such as specimen types (serum or cerebrospinal fluid) and interpretation (IgM as a marker of current infection), are provided to frame coding and utilization discussions. Data not available in the input will be noted as such in specific sections.
Billing Code Overview
CPT code 86778 describes an immunoassay performed by a laboratory analyst to detect IgM antibodies to Toxoplasma in a patient’s serum or cerebrospinal fluid. The presence of Toxoplasma IgM antibodies indicates current infection with toxoplasmosis, a parasitic infection commonly associated with exposure to contaminated cat feces.
Service Type: Laboratory infectious disease serology testing
Typical Site of Service: Clinical laboratory or hospital laboratory
Clinical & Coding Specifications
Clinical Context
A 28-year-old pregnant woman presents to her obstetric clinic with recent onset of fever, lymphadenopathy, and flu-like symptoms after potential exposure to cat feces. Her obstetrician orders serologic testing to evaluate for acute toxoplasma infection because maternal IgM positivity can indicate recent infection with risk to the fetus. A phlebotomy technician collects a serum specimen and sends it to the hospital clinical laboratory. A medical laboratory scientist or immunology technologist performs an immunoassay to detect IgM antibodies to Toxoplasma gondii, documents assay method and results in the laboratory information system, and the laboratory director reviews and signs out the final report. The result, combined with IgG testing and clinical correlation, informs the clinician’s risk assessment and counseling.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the professional (interpretation) portion of a lab procedure if separated under payer rules. |
TC | Technical component | Use when billing only the technical portion of the test (laboratory equipment, technician) and the facility performs the assay. |