Summary & Overview

CPT 86771: Immunoassay for Serum Antibodies to Shigella

CPT code 86771 denotes an immunoassay for detection of serum antibodies to Shigella and is used to document laboratory evaluation for Shigella exposure or infection. As a laboratory diagnostic code, it supports clinical decision-making for suspected enteric infection and public health surveillance of Shigella cases. Nationally, accurate capture of this service matters for epidemiology, appropriate clinical follow-up, and laboratory billing transparency.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication outlines how payers commonly categorize and reimburse serologic testing for Shigella, and identifies where policy guidance or coverage language may affect billing and claim adjudication.

Readers will learn the clinical context for ordering an anti-Shigella immunoassay, the typical site-of-service for the test, and the role of CPT code 86771 in laboratory claims. The summary highlights common billing modifiers and the practical implications for documentation and claims processing. Data elements that were not provided in the input, such as associated taxonomies, ICD-10 linkage, and payer-specific reimbursement rates, are noted as unavailable where applicable.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare86771CPTShigellaserologyimmunoassaylaboratoryinfectious-diseasediagnostic-testing

Billing Code Overview

CPT code 86771 describes an immunoassay performed by a laboratory analyst to evaluate serum antibodies to Shigella. The service is a laboratory diagnostic test that detects host antibody response to Shigella species, supporting clinical evaluation of suspected or recent Shigella infection.

Typical site of service: clinical laboratory or hospital laboratory where blood specimens are processed and analyzed. The service is performed on serum samples collected from the patient and interpreted by laboratory personnel.

Clinical & Coding Specifications

Clinical Context

A patient presents to an outpatient clinic or emergency department with acute febrile gastroenteritis characterized by diarrhea, abdominal cramping, fever, and sometimes bloody stools after recent travel or an outbreak exposure. The clinician collects a serum sample to evaluate for post-infectious or ongoing immune response to enteric pathogens. The clinical laboratory performs an immunoassay to detect serum antibodies to Shigella using 86771. Typical workflow: clinician documents symptoms and orders enteric infectious disease testing; phlebotomy obtains serum; specimen is sent to the hospital or reference laboratory; a laboratory analyst runs the immunoassay (serology) for Shigella antibodies; results are returned to the ordering provider for interpretation in the context of stool testing, culture, and PCR where available. Typical site of service: hospital outpatient laboratory, reference laboratory, or clinical laboratory associated with an ambulatory care clinic. Service type: laboratory immunoassay (serologic antibody testing).

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when only the professional component (interpretation) of the lab service is billed separately from the technical component.
`TC`	Technical component	Use when only the technical component (laboratory processing, instruments, and staff) is billed.
`90`	Reference (outside) laboratory	Use when testing is performed by a qualified independent outside laboratory and billed to the payer under the performing lab.
`59`	Distinct procedural service	Use when this assay is distinct from other services on the same day (rare for standalone serology) and documentation supports separate service.
`52`	Reduced services	Use when the assay was partially completed or performed at a reduced level versus the full procedure.
`53`	Discontinued procedure	Use when testing was begun but discontinued for patient or system reasons before completion.
`22`	Increased procedural services	Use when work required is substantially greater than typical (document specific reasons for increased complexity).
`76`	Repeat procedure by same physician (Note: not in provided list)	Data not available in the input.
`90` is included above; the list restricts to provided modifiers — use `59`, `26`, `TC`, `52`, `53`, `22`, `11`, `62`, `80`, `82`.

Taxonomy Code	Specialty	Notes
`207Q00000X`	Infectious Disease Physician	Interprets complex serologic results and guides treatment decisions.
`207L00000X`	Pathology & Laboratory Medicine	Laboratory directors and pathologists overseeing serologic testing protocols.
`363LF0000X`	Clinical Laboratory Scientist	Performs and documents the immunoassay testing workflow.
`207R00000X`	Emergency Medicine Physician	Orders testing for acute presentations in the ED.
`208D00000X`	Family Medicine Physician	Orders outpatient serology during ambulatory evaluation of gastroenteritis.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`A03.0`	Shigellosis due to Shigella dysenteriae	Direct bacterial infection by Shigella species; serology may support diagnosis in subacute or post-infectious evaluation.
`A03.1`	Shigellosis due to Shigella flexneri	Common Shigella species causing gastroenteritis; antibody testing can document immune response.
`A03.2`	Shigellosis due to Shigella boydii	Alternative Shigella species associated with enteric infection; serology may aid epidemiologic investigation.
`A03.3`	Shigellosis due to Shigella sonnei	Frequently isolated species in many regions; serologic assays can complement culture/PCR.
`A09`	Infectious gastroenteritis and colitis, unspecified	When specific organism not yet identified, serology may help determine Shigella as the etiology.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`87205`	Culture, presumptive, pathogenic organisms, multiple types; stool, bacterial, including Shigella – presumptive identification	Stool culture may be performed before or alongside serology to directly detect Shigella organisms.
`87471`	Infectious agent detection by nucleic acid (DNA or RNA); Shigella species, direct probe technique	Molecular testing (PCR) for Shigella is commonly ordered in parallel for faster, direct pathogen detection.
`87045`	Urine culture, bacterial, colony count (used as example for culture workflows)	Culture methods for enteric pathogens complement serology when assessing active infection; in enteric testing context, stool cultures like `87205` are more specific.
`86318`	Immunoassay for infectious agent antibody, quantitative, multiple-step method	General immunoassay code often used for serologic testing platforms; `86771` is specific for Shigella antibody assay.