Summary & Overview
CPT 86684: Haemophilus influenzae Antibody Immunoassay
CPT code 86684 identifies an immunoassay performed on serum to detect antibodies to Haemophilus influenzae. This serologic test is clinically relevant for evaluating immune status or prior exposure to a pathogen that can cause serious invasive disease, including meningitis and pneumonia, often affecting children. Nationally, laboratory testing codes such as 86684 support surveillance, diagnosis, and management of vaccine-preventable and infectious diseases, and they inform clinical and public health decision-making.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise summary of the code's clinical context, typical service and site of service, and common billing modifiers associated with laboratory services when available. The publication outlines benchmarks where available, highlights relevant coding and billing considerations, and summarizes policy or coverage notes that commonly affect laboratory antibody testing. Clinical context describes when the assay is ordered and its role in diagnosis and monitoring. If specific payer policies, reimbursement benchmarks, or associated taxonomies and ICD-10 pairings are not provided in the input, this content will note that such data is not available in the input.
Billing Code Overview
CPT code 86684 describes an immunoassay for detection of antibodies to Haemophilus influenzae in a patient's serum. The test evaluates the presence of specific antibodies that indicate prior exposure or immune response to Haemophilus influenzae, a bacterium implicated in invasive infections such as meningitis and pneumonia, particularly in pediatric populations.
Service type: Laboratory serologic testing (immunoassay)
Typical site of service: Clinical laboratory or hospital laboratory, with specimen collection commonly performed in outpatient clinics, hospital outpatient departments, or inpatient settings as indicated by clinical need.
Clinical & Coding Specifications
Clinical Context
A 3-year-old child presents to the pediatric clinic with fever, lethargy, and signs concerning for meningitis after several days of upper respiratory symptoms. The clinician obtains blood and cerebrospinal fluid (CSF) samples and orders laboratory testing, including serologic assessment for Hib (Haemophilus influenzae type b) antibodies to evaluate immune response or exposure. A phlebotomy technician collects a serum specimen; the specimen is transported to the hospital infectious disease laboratory. A medical laboratory scientist performs an immunoassay to detect and quantify antibodies to Haemophilus influenzae. Results are reviewed by a pathologist or clinical laboratory director and reported to the ordering pediatrician, who integrates the serology with culture, PCR, and clinical findings to guide management and public health reporting.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when reporting only the laboratory professional interpretation or consultative component separate from technical testing. |
59 | Distinct procedural service | Use when another unrelated lab service is performed the same day and needs to be distinguished as separate. |
90 | Reference (outside) lab | Use when the immunoassay is performed by an outside independent laboratory and billed through the ordering facility. |
91 | Repeat clinical diagnostic lab test | Use when the same antibody test is repeated on a separate specimen to confirm results. |
52 | Reduced services | Use if the assay was partially completed or performed with reduced methodology. |
53 | Discontinued procedure | Use if testing was started but discontinued for documented clinical reasons. |
59 | Distinct procedural service | Use when this immunoassay is distinct from other services provided on the same date (listed intentionally for emphasis). |
90 | Reference (outside) lab | Use when testing is sent to an external commercial lab rather than performed in-house (listed intentionally for emphasis). |
91 | Repeat clinical diagnostic lab test | Use for repeat testing due to discrepant or indeterminate initial results (listed intentionally for emphasis). |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 204RO0400X | Clinical Pathology | Pathologists who oversee laboratory testing and result interpretation. |
| 207RC0000X | Allergy & Immunology | Allergists/immunologists ordering serologic evaluation for immune status or vaccine response. |
| 207L00000X | Infectious Disease | Infectious disease specialists managing suspected Hib infections and interpreting serology. |
| 174400000X | Pediatrics | Pediatricians ordering testing for children with suspected invasive Hib disease. |
| 261QM0800X | Clinical Laboratory | Medical laboratory scientists and facilities performing the immunoassay. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
G00.0 | Hemophilus meningitis | Directly indicates meningitis caused by Haemophilus influenzae; serology may support diagnosis or assess immune response. |
A49.2 | Hemophilus influenzae infection, unspecified site | Used when Hib infection is identified but specific site is not documented; serology helps establish exposure. |
J15.2 | Pneumonia due to Hemophilus influenzae | Hib can cause pneumonia; antibody testing may be part of etiologic investigation or epidemiology. |
R50.9 | Fever, unspecified | Fever is a common presenting sign prompting diagnostic testing including Hib serology in children. |
R65.10 | Systemic inflammatory response syndrome (SIRS) of infectious origin without organ dysfunction | Severe systemic response where broad infectious workup, including Hib serology and cultures, may be obtained. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
86684 | Antibody; Haemophilus influenzae (Hib) (e.g., IgG, IgM) immunoassay | Primary procedure: immunoassay performed to detect antibodies to Hib in patient serum. |
87070 | Culture, bacterial, any source, with isolation and presumptive identification of isolates | May be performed on blood or CSF to identify Hib organism in suspected invasive infection. |
87449 | Infectious agent detection by nucleic acid (e.g., PCR); Haemophilus influenzae, direct probe technique | Molecular testing performed on CSF or respiratory specimens to detect Hib DNA, complementary to serology. |
81025 | Urinalysis, automated, with microscopy | Routine screening test in febrile children; not directly diagnostic but often ordered in the same clinical visit. |
86769 | Antibody; respiratory syncytial virus (RSV) | Other respiratory pathogen serologies that may be ordered concurrently in differential diagnosis. |