Summary & Overview

CPT 86631: Chlamydia Antibody Serology (Excluding IgM)

CPT code 86631 represents a laboratory serologic assay for chlamydia antibodies (excluding IgM), a technical diagnostic test typically performed on serum. This test is clinically relevant for detecting past or ongoing chlamydial infection, which has implications for sexually transmitted infection management and for non-sexual presentations such as chlamydial pneumonia and conjunctivitis. Nationally, serologic testing complements direct organism detection in specific clinical contexts and can affect public health surveillance and outpatient and inpatient diagnostic workflows.

Key payers included in the analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context and service setting, payer coverage considerations, and benchmarks where available. The publication summarizes typical sites of service and the procedural nature of the test, highlights common billing modifiers associated with laboratory services (provided in the input), and notes when input data were unavailable.

This executive summary prepares clinicians, billing professionals, and policy analysts to understand where CPT code 86631 fits within diagnostic pathways for chlamydial infection, how it is commonly delivered, and which national payers are relevant to coverage discussions. Data not available in the input are explicitly identified in the detailed sections.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare86631CPTlaboratoryserologychlamydiainfectious-diseasediagnostic-testclinical-laboratorytechnical-component

Billing Code Overview

CPT code 86631 describes a laboratory serologic test for chlamydia antibodies (excluding IgM) performed by a lab analyst. The test is a technical laboratory procedure that evaluates serum to detect antibodies indicative of chlamydial infection, which can present as a sexually transmitted infection and can also cause pneumonia and conjunctivitis.

Service type: Technical laboratory serology test
Typical site of service: Clinical laboratory or hospital laboratory setting

Data not available in the input for payers, taxonomies, ICD-10 diagnoses, and related codes.

Clinical & Coding Specifications

Clinical Context

A 24-year-old sexually active female presents to a primary care clinic with symptoms of urethral discomfort and abnormal vaginal discharge. The clinician obtains a sexual history, performs a pelvic exam, and orders laboratory testing to evaluate for common sexually transmitted infections. A blood specimen is collected and sent to the clinical laboratory for serologic testing for chlamydia antibodies excluding IgM (86631) when the clinician suspects a prior or chronic Chlamydia trachomatis infection, when nucleic acid amplification testing (NAAT) is unavailable or inconclusive, or when serologic evaluation is needed for epidemiologic or confirmatory purposes. The laboratory analyst performs the technical assay on serum, documents analytic results in the laboratory information system, and reports results to the ordering provider. Typical site of service includes outpatient clinics, hospital outpatient labs, community health centers, and reference laboratories. Turnaround time varies by lab method; results support treatment decisions, partner notification, or further diagnostic workup such as NAAT from urine or genital swabs.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing only the professional component of a lab test if the laboratory separates technical and professional components.
`TC`	Technical component	Use when billing only the technical component of the laboratory test (most common for `86631` when billed by the performing lab).
`90`	Reference (outside) laboratory	Use when the service was performed by an outside laboratory and testing was sent out.
`91`	Repeat clinical diagnostic laboratory test	Use when the same test is repeated on the same day for subsequent clinical reasons.
`59`	Distinct procedural service	Use when a separate, identifiable service needs to be distinguished from other services on the same day (careful application in lab context).
`52`	Reduced services	Use when the lab performs an abbreviated or reduced version of the test.
`53`	Discontinued service	Use when the test was started but discontinued before completion for valid clinical reasons.
`78`	Unplanned return to the operating/procedure room	Rare for lab tests; apply only if linked to an associated procedure requiring return to OR.
`90`	Reference laboratory (duplicate entry in list only once)	See above.
`91`	Repeat test (duplicate entry only once)	See above.

Taxonomy Code	Specialty	Notes
`207Q00000X`	Family Medicine	Primary care clinicians who order STI testing.
`207R00000X`	Internal Medicine	Internists ordering diagnostic testing for adult patients.
`208D00000X`	Obstetrics & Gynecology	OB/GYNs managing suspected chlamydial genital infections.
`3336C0002X`	Clinical Laboratory	Laboratory directors and clinical pathologists overseeing serologic testing.
`207L00000X`	Pediatrics	Pediatricians ordering STI screening for adolescents and young adults.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`A74.0`	Chlamydial infection of genital tract	Primary diagnosis prompting chlamydial serology or NAAT.
`A74.9`	Chlamydial infection, unspecified	Use when chlamydia infection is suspected but site not specified; may prompt serologic testing.
`J00`	Acute nasopharyngitis [common cold]	Included when respiratory symptoms lead to evaluation that may include testing for atypical pathogens; less commonly related.
`A74.3`	Chlamydial infection, pelvic inflammatory disease	Complication of genital chlamydia; serology may assist in retrospective diagnosis.
`A74.8`	Other chlamydial infections	Includes conjunctival or respiratory chlamydial infections where serology may be adjunctive.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`86631`	Tests for Chlamydia trachomatis antibody, excludes IgM — technical lab test performed on serum	Primary code for serologic testing for chlamydial antibodies (technical component).
`87320`	Infectious agent antigen detection by immunoassay, multiple-step method; Chlamydia trachomatis	Common alternative or complementary test using specimen NAAT/antigen methods for active infection.
`87491`	Infectious agent detection by nucleic acid (DNA or RNA); Chlamydia trachomatis, amplified probe technique, direct probe or NAAT for single compound	Frequently used frontline diagnostic test for acute genital chlamydial infection — often ordered alongside or instead of serology.
`87070`	Culture, bacterial; any other source except urine, blood or stool, aerobic, with isolation and presumptive identification	May be used when culture-based methods are required for non-genital sites such as conjunctival or respiratory specimens.
`86580`	Skin test; tuberculosis, intradermal (Mantoux)	Not directly related to chlamydia testing; included only if broader STI or infectious disease panels are performed — otherwise Data not available in the input.