Summary & Overview
CPT 86043: Acetylcholine Receptor Modulating Antibody Assay for Myasthenia Gravis
CPT code 86043 covers laboratory testing for acetylcholine receptor (AChR) modulating antibodies, commonly used to evaluate patients for myasthenia gravis (MG). The assay identifies noninfectious autoantibodies that interfere with neuromuscular transmission; detection or quantification supports clinical assessment of weakness and can guide further neurologic evaluation. Nationally, this immunology test is a key diagnostic tool in neuromuscular disorder workups and is performed in clinical and hospital laboratories.
Key payers included in the analysis are Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of clinical context for AChR modulating antibody testing, typical sites of service, and which payers commonly cover or reimburse this diagnostic service. The publication summarizes available benchmarks for utilization and reimbursement patterns, highlights relevant coverage and coding considerations affecting claim submission and adjudication, and provides clinical context linking test results to myasthenia gravis diagnosis and management pathways.
This resource is intended for billing professionals, laboratory directors, and clinicians seeking concise guidance on the purpose and payer landscape for CPT code 86043, and for policy staff monitoring diagnostic testing for autoimmune neuromuscular disease.
Billing Code Overview
CPT code 86043 evaluates a patient specimen, such as serum, for acetylcholine receptor (AChR) modulating antibody using methods like immunofluorescence assay. The test detects a noninfectious autoantibody whose presence or level can indicate myasthenia gravis (MG), an autoimmune disorder that disrupts neuromuscular transmission and causes muscle weakness.
Service Type: Immunology / Antibody Testing
Typical Site of Service: Clinical laboratory or hospital laboratory
Clinical & Coding Specifications
Clinical Context
A 48-year-old patient presents to a neurology clinic with fluctuating skeletal muscle weakness, ptosis, and fatigable diplopia. The neurologist performs a focused neuromuscular examination, documents clinical suspicion for myasthenia gravis (MG), and orders serum testing for acetylcholine receptor (AChR) antibodies to evaluate for an autoimmune etiology. A phlebotomy draw is performed in an outpatient laboratory or hospital outpatient phlebotomy suite; the specimen (serum) is sent to the clinical laboratory for immunofluorescence or other validated immunoassay to detect AChR modulating antibodies. Results are reported to the ordering neurologist, who correlates serology with clinical exam and may order electrodiagnostic testing or chest imaging (CT/MRI) to evaluate for thymoma based on results. Typical sites of service include outpatient clinics, hospital outpatient laboratories, and independent diagnostic laboratories (IDTF/CLIA-certified labs). Nursing or phlebotomy staff perform specimen collection; the laboratory performs testing and technical reporting. The provider documents indication, specimen source, and correlation with signs and symptoms in the medical record.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier | Standard reporting when no modifier applies to the test |
26 | Professional component | When the billing physician reports only the professional interpretation or consultation for the laboratory result
TC | Technical component | When the laboratory bills only for the technical component of testing (equipment, reagents, personnel)
90 | Reference laboratory | When the specimen is forwarded to an external reference laboratory that performs the test
QW | CLIA waived test | Rarely applicable; use only if the specific kit/method is CLIA-waived for this analyte
QX | Certified lab subcontracted testing | When an independent laboratory performs testing under contract with a CLIA-certified entity
QY | Laboratory performing under CLIA provider-performed microscopy rules | If applicable when provider-performed testing meets specific CLIA criteria
52 | Reduced services | If specimen or testing is limited and full testing algorithm not completed
53 | Discontinued procedure | If testing was initiated but specimen compromised and testing discontinued
90 | Duplicate entry avoided by reusing 90 above to indicate reference lab | See 90 entry
59 | Data not listed in provided modifier list; excluded per instructions | Not applicable
| Taxonomy Code | Specialty | Notes |
|---|---|---|
207RG0100X | Neurology | Ordering specialists who evaluate for myasthenia gravis and interpret results in clinical context |
207RH0005X | Clinical Neurophysiology | Specialists who may correlate antibody results with electrodiagnostic studies
207RC0000X | Allergy & Immunology | Specialists involved in autoimmune neuromuscular evaluation and interpretation
208000000X | Pathology & Laboratory Medicine | Laboratory directors and pathologists overseeing serologic testing and validation
261QA1900X | Phlebotomy | Providers and facilities performing specimen collection and handling
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
G70.00 | Myasthenia gravis without (acute) exacerbation | Primary diagnosis in which AChR antibody testing is indicated to confirm autoimmune etiology |
G70.01 | Myasthenia gravis with (acute) exacerbation | Used when patient has worsening weakness; antibody testing may guide management
G70.9 | Myasthenia gravis, unspecified | General code when specifics not documented; correlates with need for serologic testing
R53.83 | Other fatigue | Symptom prompting evaluation for neuromuscular causes including MG
H53.8 | Other visual disturbances (includes diplopia) | Diplopia is a common presenting symptom that prompts AChR antibody testing
M62.81 | Muscle weakness (generalized) | Non-specific weakness leading to neuromuscular workup including AChR antibody testing
C37.9 | Malignant neoplasm of thymus, unspecified | Thymoma association with MG; positive antibodies may prompt chest imaging for thymic pathology
Z13.6 | Encounter for screening for neurological disorders | May be used for targeted screening in high-risk patients where antibody testing is performed
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
86043 | Acetylcholine receptor (AChR) modulating antibody; immunofluorescence assay | Primary test that detects AChR-modulating antibodies used in evaluation of myasthenia gravis |
83519 | Drug assay, qualitative; multiple drug classes (e.g., immunosuppressant therapeutic drug monitoring may use other assays) | May be ordered concurrently when monitoring immunosuppressant therapy in MG patients
95886 | Needle electromyography, prostatic? (Note: placeholder) | Data not available in the input.
70543 | Magnetic resonance imaging, brain, without and with contrast (used for central causes of weakness) | Ordered when alternative central nervous system pathology is considered in the diagnostic workup
71045 | Chest radiograph, single view, frontal | Used in initial imaging to evaluate for mediastinal mass, though CT chest is preferred for thymoma evaluation
71260 | CT chest with contrast | Frequently performed to evaluate for thymoma in patients with confirmed or suspected myasthenia gravis