Summary & Overview
CPT 86793: Yersinia Antibody Immunoassay, Serum
CPT code 86793 designates a laboratory immunoassay for detection of serum antibodies to Yersinia species, organisms that can cause gastroenteritis and reactive arthritis. This code matters nationally because serologic testing for Yersinia supports diagnostic evaluation of enteric infections and post-infectious sequelae, influencing clinical management and public health tracking. Laboratory reimbursement and coding clarity for this immunoassay impact hospital and outpatient lab billing workflows across payers.
Key payers covered include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find context on the clinical indications for Yersinia antibody testing, typical sites of service (clinical and hospital laboratories), and the role of this test in differential diagnosis of gastroenteritis and reactive arthritis. The publication also outlines what to expect in payer coverage discussions, common modifier usage patterns (listed separately), and where benchmarks and policy updates would affect claims processing. Data not available in the input is noted where applicable.
This overview equips billing professionals, laboratory managers, and clinicians with a concise reference to CPT code 86793, clarifying its clinical purpose and the payer landscape relevant to national billing practices.
Billing Code Overview
CPT code 86793 describes an immunoassay performed on patient serum to detect antibodies to Yersinia, a bacterial genus associated with gastroenteritis and reactive arthritis. The service involves laboratory analysis of a blood-derived specimen to evaluate immune response indicating recent or past infection.
Service type: Clinical laboratory immunoassay
Typical site of service: Clinical laboratory or hospital laboratory setting
Clinical & Coding Specifications
Clinical Context
A 28-year-old adult presents to primary care with acute onset abdominal pain, fever, and diarrhea after recent consumption of undercooked pork. The clinician documents suspected bacterial gastroenteritis and orders serologic testing to evaluate for Yersinia infection when stool culture is negative or the patient presents later in disease course. A phlebotomy technician obtains a serum specimen and sends it to the clinical laboratory. A laboratory analyst performs an immunoassay to detect antibodies to Yersinia species, reported under 86793. Results are reviewed by the ordering clinician to confirm recent or past exposure and to help differentiate causes of enteritis or explain post-infectious reactive arthritis. Typical workflow steps: specimen collection in an outpatient clinic or hospital, specimen accessioning and processing in a clinical laboratory, performance of immunoassay by trained technologist, result verification by lab director, and reporting to the ordering provider in the electronic health record.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier | Default reporting when no specific modifier applies |
11 | Professional component | When billing only the professional interpretation component of the test |
26 | Professional component | When only the physician interpretation is billed separate from technical services |
TC | Technical component | When billing only the technical component (laboratory performance and materials) |
90 | Reference laboratory | When the test is performed by an outside reference laboratory |
52 | Reduced services | When the test is partially performed or limited in scope |
53 | Discontinued procedure | When testing was started but discontinued for clinical reasons |
62 | Two surgeons/dual specialists | Rarely applicable; use if two qualified labs/providers share responsibility for testing interpretation |
78 | Return to operating room | Not typically applicable; included for cases where testing supports intraoperative care |
80 | Assistant surgeon | Not typically applicable; use only if applicable to billing context |
QK | Medical direction of qualified non-physician by physician | When physician provides medical direction for non-physician staff performing services |
QX | Certified nurse-midwife, CRNA, or other | When a qualified non-physician practitioner performs the service under supervision |
QY | Medical direction of physician assistant, NP, or CNS | When physician directs a PA, NP, or CNS performing the service |
U1 | Presence of a specific test condition | When a payer-defined specific condition or program requires this modifier |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 201R00000X | Pathology & Laboratory Medicine | Laboratory directors and clinical pathologists overseeing serology testing |
| 208000000X | Family Medicine | Primary care clinicians ordering Yersinia serology for outpatient gastroenteritis evaluation |
| 207Q00000X | Internal Medicine | Hospitalists and internists who order and interpret infectious disease testing |
| 2084P0800X | Emergency Medicine | Emergency clinicians who order testing during acute presentations |
| 335600000X | Infectious Disease | Specialists who evaluate complex or post-infectious sequelae such as reactive arthritis |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
A04.5 | Campylobacter enteritis | Differential diagnosis for bacterial gastroenteritis; serology helps distinguish causes when culture is negative |
A04.2 | Enterocolitis due to Escherichia coli | Common bacterial enteritis considered alongside Yersinia when evaluating diarrheal illness |
A09 | Infectious gastroenteritis and colitis, unspecified | General presenting diagnosis when stool studies are pending; serology may clarify etiology later |
A49.9 | Bacterial infection, unspecified | Used when bacterial etiology is suspected but not yet identified; serology can provide supporting evidence |
M02.3 | Reactive arthropathy following intestinal infection | Post-infectious complication associated with Yersinia; serology can support a causal link |
R19.7 | Diarrhea, unspecified | Symptom-focused diagnosis prompting stool and serologic testing for enteric pathogens |
R10.9 | Abdominal pain, unspecified | Common presenting complaint leading to evaluation for infectious causes including Yersinia |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
87045 | Culture, bacterial, other source, screening only, with isolation and presumptive identification of isolates | Stool or wound culture performed when bacterial enteritis is suspected; may be ordered before or alongside serology |
87471 | Infectious agent detection by nucleic acid (DNA or RNA); Salmonella, single organism | Molecular stool testing for specific enteric pathogens that can be ordered concurrently to identify etiologic agents |
87520 | Infectious agent antigen detection by immunoassay, multiple organisms (e.g., GI panel), each | Rapid antigen immunoassays or multiplex panels used in acute gastroenteritis workup alongside serology for retrospective confirmation |
86038 | Antibody; infectious agent, titer, each | Serologic titers that may be ordered to quantify antibody response to various pathogens, analogous to 86793 for Yersinia |
99000 | Handling and/or conveyance of specimen | Ancillary service codes for specimen handling and transport that support laboratory testing workflows |