Summary & Overview
CPT 0545U: AChR Live Cell–Based Immunofluorescence Assay
CPT code 0545U designates a Proprietary Laboratory Analyses (PLA) test for the AChR Live Cell–Based Assay from Neurocode USA Inc., which detects acetylcholine receptor antibodies by immunofluorescence on live cells. This code matters nationally because it identifies a single-manufacturer, highly specific diagnostic assay used in neuromuscular disease evaluation; clear code assignment supports accurate billing, coverage decisions, and tracking of utilization for a targeted laboratory service. Key payers considered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare.
Readers will find a concise breakdown of clinical context — the assay’s role in identifying AChR antibodies — and what to expect in payer coverage discussions for a PLA test. The publication provides benchmarking guidance on where this code fits within laboratory service lines, outlines common billing considerations, and summarizes national policy context relevant to proprietary lab tests. Data gaps are noted where input lacked payer-specific coverage policies, associated taxonomies, or ICD-10 linkage; those fields are identified as "Data not available in the input." The content is aimed at billing managers, laboratory directors, and policy analysts who need a clear, national-level reference for CPT code 0545U and its clinical application.
Billing Code Overview
CPT code 0545U is a Proprietary Laboratory Analyses (PLA) code that applies exclusively to the AChR Live Cell–Based Assay produced by Neurocode USA Inc. The test identifies acetylcholine receptor (AChR) antibodies using an immunofluorescence technique with live cells. Results are reported as positive or negative, indicating the presence or absence of AChR antibodies.
Service type: Laboratory diagnostic test — immunofluorescence live cell assay
Typical site of service: Outpatient laboratory or reference diagnostic facility
Data not available in the input for associated taxonomies, ICD-10 diagnoses, and related codes.
Clinical & Coding Specifications
Clinical Context
A 48-year-old patient presents to a neurology clinic with fluctuating skeletal muscle weakness, ptosis, and diplopia suspicious for myasthenia gravis. The neurologist performs a focused history and physical exam, documents ocular and bulbar symptoms, and orders laboratory testing to confirm autoimmune etiology. The clinician places an order for the AChR Live Cell–Based Assay (Proprietary Laboratory Analyses code 0545U) performed by Neurocode USA Inc. A phlebotomy visit is scheduled at an outpatient laboratory or hospital outpatient draw station; blood is collected in the appropriate tube, labeled, and shipped to the performing laboratory per manufacturer instructions. Results are reported as positive or negative for acetylcholine receptor (AChR) antibodies and are entered into the electronic health record. The result guides diagnostic confirmation of AChR antibody–positive myasthenia gravis, informs decisions about additional testing (e.g., anti–MuSK antibodies, repetitive nerve stimulation, single-fiber EMG), and supports treatment planning. Typical sites of service include outpatient neurology clinics, hospital outpatient phlebotomy centers, and independent clinical reference laboratories that coordinate specimen transport to the proprietary testing laboratory.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier (default) | Use when billing the PLA 0545U under standard circumstances with no special circumstances altering payment or reporting. |
22 | Increased Procedural Services | Use when unusually extensive medical work or documentation associated with test ordering or interpretation is required beyond typical case complexity (rare for PLA testing). |
52 | Reduced Services | Use when the specimen or testing performed is partially reduced from the full protocol (e.g., partial panel or incomplete testing performed by agreement). |
53 | Discontinued Procedure | Use when collection or testing was started but discontinued for documented clinical reasons prior to completion. |
59 | Distinct Procedural Service | Use to indicate the test is distinct from other services billed on the same day when payer policy requires separation (apply only if allowed by payer). |
90 | Reference (Outside) Laboratory | Use when another laboratory performs the test on behalf of the billing provider (clarifies outside lab involvement). |
91 | Repeat Clinical Diagnostic Laboratory Test | Use when the same AChR assay is repeated on the same day for verification of prior result. |
CT | New Technology | Use if payer requires a modifier indicating a new or proprietary test (some payers use specific reporting conventions for PLA codes). |
Q0 | Investigational Clinical Service Provided in a Clinical Research Study | Use when the AChR assay is provided as part of a qualifying clinical research study and meets payer criteria for reporting. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 2084P0800X | Neurology | Neurologists commonly order the AChR live cell assay when evaluating suspected myasthenia gravis. |
| 207P00000X | Clinical Pathology | Pathologists or clinical laboratory directors oversee test performance, interpretation, and reporting workflows. |
| 363L00000X | Phlebotomy | Phlebotomists perform specimen collection, processing, and proper labeling for shipment to the performing lab. |
| 207RC0000X | Neuromuscular Medicine | Specialists in neuromuscular disorders frequently manage diagnosis and ordering of antibody testing. |
| 261QM0800X | Allergy & Immunology | Immunologists may order or interpret antibody assays in complex autoimmune evaluations. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
G70.00 | Myasthenia gravis without (acute) exacerbation | Primary diagnosis for which AChR antibody testing is indicated to confirm autoimmune AChR antibody–mediated MG. |
G70.01 | Myasthenia gravis with (acute) exacerbation | Used when patients present with worsening symptoms; AChR testing can help establish seropositivity during exacerbation. |
G70.81 | Lambert-Eaton syndrome | Differential diagnosis in neuromuscular junction disorders; antibody testing helps differentiate etiologies though different antibody panels are used. |
R25.2 | Cramp and spasm | Symptom code that may prompt evaluation including antibody testing when presentation suggests neuromuscular junction disorder. |
H02.40 | Ptosis, unspecified | Ocular ptosis is a common presenting symptom prompting AChR antibody testing to evaluate for ocular myasthenia gravis. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
80053 | Comprehensive metabolic panel | Basic serum chemistries often ordered concurrently to assess baseline metabolic status before immunologic workup. |
83516 | Immunoassay for analyte other than infectious agent antibody or infectious agent antigen; qualitative or semiquantitative, single step method (e.g., ELISA) | Other laboratory immunoassays that may be ordered in parallel or when alternative testing platforms are used; complements specialized PLA testing. |
95905 | Nerve conduction studies; needle electromyography, by physician, 1 extremity with or without related paraspinal areas | Electrodiagnostic testing commonly performed in the diagnostic workup of suspected myasthenia gravis alongside antibody testing. |
95860 | Needle electromyography, 1 extremity with or without related paraspinal areas; 1–2 muscles | Single-fiber EMG or standard EMG studies are often used after or alongside antibody testing to confirm neuromuscular transmission defects. |
86308 | Antibody; single analyte, qualitative or semiquantitative (e.g., autoantibodies) | Generic antibody test CPT sometimes used for other autoantibodies (not a substitute for PLA 0545U) and may appear in the broader testing panel. |