Summary & Overview

CPT 86794: Zika Virus IgM Immunoassay, Serum

CPT code 86794 represents a laboratory immunoassay to detect immunoglobulin M (IgM) antibodies to Zika virus in patient serum. This test identifies recent or acute Zika virus infection and is an important diagnostic tool for clinical management, public health surveillance, and screening in relevant clinical scenarios. Nationally, accurate coding and coverage of Zika IgM testing affect laboratory workflows, claim adjudication, and reporting during outbreaks.

Key payers in the analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Coverage policies and medical necessity criteria for Zika IgM testing vary across payers and between commercial and government plans; these differences influence authorization requirements, documentation expectations, and reimbursement pathways.

Readers will find an overview of the clinical purpose of the test, typical sites of service, and common billing considerations. The publication summarizes payer coverage patterns, benchmark metrics where available, and relevant administrative guidance that affects claim processing for this laboratory service. The content also provides clinical context on when IgM testing is used in patient evaluation and public health response. Data not available in the input will be noted where applicable.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare86794CPTZikaIgMserologylaboratoryinfectious-diseaseimmunoassay

Billing Code Overview

CPT code 86794 is an immunoassay for detection of immunoglobulin M (IgM) antibodies to Zika virus performed on a patient’s serum. The service involves laboratory analysis to evaluate acute or recent Zika virus infection by identifying IgM-class antibodies.

Service type: Serologic immunoassay laboratory test
Typical site of service: Clinical diagnostic laboratory or hospital laboratory setting

Clinical & Coding Specifications

Clinical Context

A 32-year-old pregnant patient presents to an outpatient infectious disease clinic after recent travel to a Zika-endemic region. She reports a transient febrile illness with rash and conjunctivitis two weeks prior. The obstetrician orders serologic testing to evaluate for recent Zika virus infection. A phlebotomy technician collects a serum specimen which is sent to the hospital reference laboratory. In the laboratory, a clinical laboratory scientist performs an immunoassay to detect immunoglobulin M (IgM) antibodies to Zika virus, documented under CPT 86794. Results are routed to the ordering provider; positive or equivocal IgM findings may prompt reflex testing (e.g., plaque reduction neutralization testing) and obstetric counseling. Typical site of service is an outpatient laboratory or hospital core laboratory; specimen collection may occur in an ambulatory clinic, emergency department, or inpatient unit.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	When reporting only the laboratory professional interpretation if separated from technical work (rare for automated immunoassays).
`90`	Reference (outside) laboratory	When the specimen testing is performed by an outside independent reference laboratory and another lab ordered the service.
`TC`	Technical component	When billing only the technical component of the test (instrumentation, reagents, personnel) separate from professional interpretation.
`52`	Reduced services	When testing is partially performed or limited relative to the full service (e.g., abbreviated panel).
`53`	Discontinued procedure	When sample handling/testing is started but aborted for valid clinical reasons.
`78`	Unplanned return to the operating/procedure room	Not typically used for laboratory testing but included when a procedure-related return mandates additional testing tied to the same operative episode.
`80`	Assistant surgeon	Not applicable to laboratory testing; used by surgical services when assistant surgeon involved.
`82`	Assistant surgeon (when qualified resident not available)	See above — generally not applicable to this lab code.
`22`	Increased procedural services	When unusually high complexity testing or extensive additional steps are required beyond standard assay processing.
`90`	Reference (outside) laboratory	When performed by a different CLIA-certified reference lab (listed to reflect common use).
`91`	Repeat clinical diagnostic laboratory test	Not provided in input list; omitted.

Taxonomy Code	Specialty	Notes
207RG0400X	Infectious Disease	Physicians who order and interpret serologic testing for viral infections including Zika.
207Q00000X	Clinical Pathology	Pathologists who oversee laboratory testing, quality control, and result interpretation.
363LA2200X	Laboratory Director	Clinical laboratory directors and supervisors who manage serologic testing operations.
261QM0800X	Obstetrics & Gynecology	OB/GYN providers who commonly order Zika testing for pregnant patients.
207P00000X	Internal Medicine	Primary care and travel medicine clinicians who evaluate febrile travelers and order Zika IgM testing.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`A92.5`	Zika virus disease	Primary diagnosis code indicating symptomatic Zika infection and directly aligned with IgM testing.
`O98.5`	Viral diseases complicating pregnancy, Zika virus	Used when Zika infection occurs in pregnancy; testing with `86794` is frequently ordered for maternal evaluation.
`A92.89`	Other mosquito-borne viral fevers	Used when a suspected arboviral infection is queried and serology for Zika is part of the diagnostic workup.
`R50.9`	Fever, unspecified	Symptom-driven indication for ordering Zika IgM testing in a patient with travel history.
`R21`	Rash and other nonspecific skin eruption	Dermatologic manifestation prompting evaluation for Zika infection with IgM serology.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`86793`	Infectious agent antibody detection by enzyme immunoassay technique, qualitative or semi-quantitative, single step method; dengue virus IgM	Performed when differentiating flavivirus infections; dengue IgM testing is commonly ordered alongside Zika IgM due to cross-reactivity and overlapping epidemiology.
`87386`	Infectious agent detection by nucleic acid (DNA or RNA); Zika virus, amplified probe technique	Molecular testing for Zika RNA may be ordered earlier in illness or for confirmation when IgM is positive; complements serologic testing.
`87476`	Infectious agent detection by nucleic acid (e.g., RT-PCR), Zika virus, amplified probe technique	Alternate molecular assay CPT often used for Zika RNA detection in serum or urine during acute infection.
`86795`	Infectious agent antibody detection by immunoassay for IgG (Zika virus)	Zika IgG testing may be performed in conjunction with IgM to assess timing of infection and potential prior exposure.
`86483`	Antibody, other viral; qualitative or semiquantitative, if used for confirmatory neutralization testing (note: PRNT has no specific CPT4 code)	Used in specialized confirmatory testing workflows when neutralizing antibody assessment is indicated after positive IgM to help distinguish cross-reactivity.