Summary & Overview
CPT 86381: Mitochondrial Antibody (M2) Enzyme Immunoassay
CPT code 86381 represents an enzyme immunoassay for detection of mitochondrial antibodies (notably M2) in serum. These antibodies are clinically significant because their presence supports diagnosis of primary biliary cholangitis (PBC), an autoimmune condition that causes progressive bile-duct injury and can lead to liver damage. Nationally, testing for mitochondrial antibodies informs diagnostic workups for cholestatic liver disease and impacts downstream clinical management and specialist referral patterns.
Key payers covered in this review include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare and Medicare. Readers will find a concise reference to the code’s clinical purpose and typical laboratory setting, alongside payer coverage context. The publication outlines common billing and coding considerations, typical places of service, and clinical indications for testing.
This summary provides bench-level orientation for clinicians, laboratory managers, and revenue cycle professionals: the clinical rationale for ordering the test, where it is typically performed, and which major payers are included in coverage discussions. Data not available in the input for items such as associated taxonomies, specific ICD-10 pairings, and detailed coverage policies are noted as not provided.
Billing Code Overview
CPT code 86381 describes a laboratory immunoassay for the detection of mitochondrial antibodies (for example, M2) in a patient specimen such as serum. The test is typically performed using an enzyme immunoassay (EIA) method to identify antibodies associated with autoimmune liver disease.
Service type: Immunology laboratory test — antibody assay
Typical site of service: Clinical laboratory or hospital laboratory, where serum specimens are collected and analyzed for autoantibodies related to liver disease.
Clinical & Coding Specifications
Clinical Context
A 52-year-old woman presents to hepatology clinic with progressive fatigue, pruritus, and mildly elevated alkaline phosphatase on routine chemistry. The hepatologist suspects autoimmune cholestatic liver disease and orders serologic testing, including a mitochondrial antibody panel to detect anti-mitochondrial antibodies (especially M2 subtype). A phlebotomy sample of serum is collected in the outpatient laboratory and shipped to a clinical immunology laboratory where an enzyme immunoassay (EIA) is performed. Results reporting documents presence or absence of mitochondrial antibodies; a positive anti‑M2 supports a diagnosis of primary biliary cholangitis (PBC) and informs prognosis and further management such as referral to hepatology, imaging, and possible ursodeoxycholic acid therapy. Typical site of service is an outpatient clinic or hospital outpatient laboratory; ordering providers commonly include gastroenterologists, hepatologists, and primary care physicians. Billing uses the immunology/laboratory service CPT code 86381 for the mitochondrial antibody assay, with laboratory technical and, if applicable, professional components documented per institutional billing policy.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
TC | Technical component | Use when billing only the laboratory technical component (instrumentation, personnel) of the assay. |
26 | Professional component | Use when billing only the professional component (interpretation, report) of the assay. |
90 | Reference laboratory | Use when the specimen is forwarded to an outside/reference laboratory for testing. |
91 | Repeat clinical diagnostic laboratory test | Use when the test is repeated on the same day to obtain a valid result. |
52 | Reduced services | Use when the test is partially performed or a reduced service is provided. |
53 | Discontinued procedure | Use when specimen collection or testing was started but discontinued for clinical reasons. |
59 | Distinct procedural service | Use when reporting a distinct unrelated service on the same day that could be bundled. |
90 | Modifier 90 is already listed above | |
90 | Duplicate entry avoided | |
91 | Duplicate entry avoided |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 207RC0000X | Gastroenterology | Hepatologists and gastroenterologists order and interpret autoimmune liver serologies. |
| 208000000X | Family Medicine | Primary care providers order initial liver panels and refer to specialists. |
| 207RH0000X | Internal Medicine | Hospitalists and internists may order testing during inpatient evaluation of liver disease. |
| 1223P0001X | Clinical Pathology | Laboratory directors and clinical pathologists oversee test validation and reporting. |
| 2086M0900X | Emergency Medicine | May order when evaluating acute presentations with abnormal liver tests. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
K73.0 | Chronic persistent hepatitis | Differential diagnosis for chronic liver enzyme abnormalities prompting autoimmune serology. |
K74.3 | Primary biliary cirrhosis | Historical term; corresponds to primary biliary cholangitis (PBC) and is directly associated with positive anti‑mitochondrial antibodies. |
K83.1 | Obstruction of bile duct | Biliary obstruction can present with cholestatic enzymes; testing helps differentiate autoimmune causes. |
K76.0 | Fatty (change of) liver, not elsewhere classified | Common comorbidity; liver testing often ordered concurrently. |
R63.5 | Abnormal weight gain | Symptom codes like fatigue or weight changes may trigger broader workup including 86381. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
80076 | Hepatic function panel | Common laboratory panel ordered with 86381 to assess liver enzymes and cholestatic pattern. |
84460 | Thyroid stimulating hormone (TSH) | Often ordered in workup of fatigue and abnormal liver tests as part of differential diagnosis. |
83020 | Hemoglobin; glycosylated (A1c) | Ordered in general chronic disease evaluation when metabolic contributors are considered. |
87086 | Culture, bacterial; quantitative colony count | May be ordered if infectious cholangitis is a concern in the clinical workflow. |
83516 | Albumin; urine or serum | Serum albumin is part of assessing synthetic liver function during evaluation for PBC. |