Summary & Overview
CPT 86618: Immunoassay for Borrelia burgdorferi Antibodies
CPT code 86618 represents a laboratory immunoassay used to detect antibodies to Borrelia burgdorferi in blood or cerebrospinal fluid, providing serologic evidence of Lyme disease. Nationally, serologic testing for Lyme disease is a key component of diagnostic workflows, informing clinical decisions for patients with compatible symptoms and exposure history. Laboratory performance, coding accuracy, and payer coverage policies affect access and reimbursement for this diagnostic service.
Key payers included in this analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context for serologic testing, typical sites of service and service type, common billing modifiers associated with laboratory services, and notes on related coding considerations. The publication covers national benchmarks and policy updates relevant to laboratory diagnostics where available; if specific payer policies or numeric benchmarks are not present in the source data, the text will indicate that data is not available in the input.
This summary is intended for health policy analysts, billing professionals, and laboratory administrators who need a clear, national-level briefing on coding, clinical purpose, and payer coverage context for CPT code 86618.
Billing Code Overview
CPT code 86618 describes an immunoassay performed by a laboratory analyst to detect antibodies to Borrelia burgdorferi, the bacterium that causes Lyme disease. The test evaluates a patient’s blood or cerebrospinal fluid (CSF) sample to identify serologic evidence of infection.
Service Type: Laboratory diagnostic immunoassay
Typical Site of Service: Clinical laboratory or hospital laboratory; blood draw may occur in an outpatient clinic or phlebotomy collection site; CSF testing requires prior lumbar puncture performed in an inpatient or outpatient procedural setting.
Clinical & Coding Specifications
Clinical Context
A typical patient is an adult presenting to an outpatient clinic or emergency department with a history of tick exposure, erythema migrans, new onset arthralgias, facial palsy, or unexplained febrile illness after travel to a Lyme-endemic area. The clinician orders serologic testing to evaluate for antibodies to Borrelia burgdorferi. A phlebotomist collects a blood specimen (serum) and sends it to a hospital or reference laboratory. In the laboratory, a medical technologist or lab analyst performs an immunoassay (enzyme immunoassay or immunofluorescence) on serum or cerebrospinal fluid to detect IgM and/or IgG antibodies to Borrelia burgdorferi. Results are reported to the ordering provider; positive or equivocal immunoassays are frequently reflexed to confirmatory testing (e.g., Western blot or specific immunoblot) as part of established laboratory protocols. Typical sites of service include outpatient clinics, urgent care centers, hospital inpatient laboratories, and independent clinical reference laboratories.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when reporting only the professional interpretation component performed by a qualified physician or pathologist separate from the technical lab work |
TC |