Summary & Overview
CPT 86788: West Nile Virus IgM Immunoassay
CPT code 86788 describes an immunoassay to detect IgM antibodies to West Nile virus (WNV) in serum or cerebrospinal fluid, used to identify recent or acute infection that can lead to meningoencephalitis. Nationally, accurate laboratory detection of WNV IgM is important for clinical decision-making, public health surveillance, and outbreak response during mosquito-borne transmission seasons.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical purpose of the test, typical sites of service, and payer relevance. The publication outlines common billing considerations, typical modifiers used with laboratory services, and where available summarizes coverage touchpoints and reimbursement context across major payers.
This resource provides clinical context for when CPT code 86788 is used, clarifies the specimen types (serum and CSF), and highlights its role in diagnosing neurologic infection. It also points to areas where further documentation or laboratory confirmation may be relevant. Data not provided in the input—such as specific ICD-10 pairings, associated taxonomies, and payer-specific reimbursement rates—is noted as unavailable in the input.
Billing Code Overview
CPT code 86788 is an immunoassay performed by a laboratory analyst to detect IgM antibodies to West Nile virus (WNV) in a patient’s serum or cerebrospinal fluid (CSF). The test assists in diagnosing recent or acute WNV infection, which can cause meningoencephalitis and other neurologic manifestations.
Service type: Clinical laboratory infectious disease serology (immunoassay for WNV IgM)
Typical site of service: Hospital laboratory, independent reference laboratory, or outpatient clinical laboratory, with specimen collection occurring in outpatient clinics, emergency departments, or inpatient settings depending on clinical presentation.
Clinical & Coding Specifications
Clinical Context
A middle-aged patient presents to the emergency department during mosquito season with acute onset fever, severe headache, photophobia, neck stiffness, and confusion. The clinician orders laboratory testing for neuroinvasive arboviral infections given focal neurologic signs and cerebrospinal fluid (CSF) pleocytosis after lumbar puncture. A serum sample and CSF are sent to the clinical laboratory for immunoassay detection of West Nile virus (WNV) specific IgM antibody using the procedure coded as 86788. The laboratory analyst performs the immunoassay on the patient’s serum and/or CSF, documents assay controls and results in the laboratory information system, and reports positive or negative IgM findings to the ordering clinician and infectious disease team to guide patient management and public health reporting. Typical site of service includes hospital inpatient wards, emergency departments, and outpatient clinics where lumbar puncture and blood draw can be performed; testing is usually processed in hospital or reference microbiology laboratories.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when billing only the professional (interpretation) portion of the test separated from the technical component. |