CPT code 86789 represents an immunoassay performed on serum or cerebrospinal fluid to detect antibodies other than IgM to West Nile virus (WNV). This serologic test supports diagnosis of prior or ongoing WNV infection, including neuroinvasive presentations such as meningoencephalitis, and informs clinical management and public health surveillance. Nationally, WNV testing is an element of arboviral disease workups and laboratory public-health coordination, making this code relevant for hospitals, reference laboratories, and outpatient testing centers.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication outlines expected use cases for the assay, typical sites of service, and how this code fits into laboratory service lines. Readers will find benchmarks for utilization and reimbursement (where available), summary clinical context for when non-IgM antibody testing is used versus other WNV assays, and notes on payer coverage patterns and billing considerations. Data not available in the input is noted where applicable. The content is intended for billing professionals, laboratory managers, and policy analysts seeking a concise reference to CPT code 86789 and its clinical and billing context.