CPT 81183 ATXN10 Expanded Allele Reimbursement

CPT code 81183 covers a molecular diagnostic laboratory procedure to detect expanded sequence alleles in the ataxin 10 gene (ATXN10). This genetic test identifies abnormal allele expansions that can be clinically relevant for disorders linked to ATXN10. As a specialized molecular service performed in clinical or reference genetics laboratories, CPT code 81183 supports diagnostic confirmation, family counseling, and disease management decisions in neurology and genetics care pathways.

Key national payers included in the coverage landscape are Aetna, Blue Cross Blue Shield plans, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of billing and coding context for CPT code 81183, typical sites of service, common modifiers used with molecular laboratory services, and the clinical scenarios in which ATXN10 expanded allele testing is ordered. The publication provides benchmarks and policy-relevant points about reimbursement practices and payer coverage trends where available. Clinical context explains the purpose of expanded allele detection and its role in diagnostic workflows. If specific payer policy details, taxonomies, ICD-10 mappings, or related codes are not available in the input, the report notes that those items are not provided.

Billing Code Overview

CPT code 81183 describes a laboratory technical procedure to detect expanded sequence alleles in the ataxin 10 gene (ATXN10) by a lab analyst. This service is a molecular genetic test focused on identifying abnormal allele expansions in the ATXN10 gene.

Service type: Genetic testing (molecular diagnostic assay)
Typical site of service: Clinical molecular diagnostics laboratory or specialized genetic testing laboratory

Data not available in the input.

Clinical Context

A 42-year-old patient with a family history of spinocerebellar ataxia and progressive gait instability is referred by a neurologist for genetic testing to evaluate for repeat expansion in the ataxin 10 gene (ATXN10). The clinical workflow begins with the neurologist obtaining informed consent and a detailed family and clinical history documenting ataxia symptoms. A blood specimen (or buccal/saliva specimen per laboratory policy) is collected in an appropriate tube, labeled, and shipped to a molecular genetics laboratory. The laboratory performs DNA extraction, PCR-based or repeat-primed PCR testing and/or fragment analysis to detect expanded repeat alleles in ATXN10. Results are analyzed by a molecular pathologist or lab director, a technical report is generated describing presence or absence of expanded alleles, number of repeats if quantifiable, interpretation, and any testing limitations. The finalized report is transmitted to the ordering neurologist who discusses findings and implications for diagnosis, prognosis, and family testing. Typical site of service is an outpatient molecular diagnostics laboratory supporting ambulatory neurology clinics or hereditary disease specialty centers.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	Use when billing only the professional interpretation/reporting portion by a pathologist or laboratory director separate from the technical test.

Taxonomy Code	Specialty	Notes
`207RP1000X`	Clinical Molecular Genetics Laboratory	Laboratories performing molecular diagnostic testing for repeat expansion disorders.
`207RN0400X`	Medical Genetics	Geneticists ordering and interpreting hereditary ataxia testing.
`2084P0200X`	Neurology	Neurologists evaluating patients with ataxia who order ATXN10 testing.
`207L00000X`	Pathology	Molecular pathologists or laboratory directors responsible for result interpretation and sign-out.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`G11.1`	Early-onset cerebellar ataxia	Represents hereditary cerebellar ataxias where ATXN10 repeat expansion testing may be clinically indicated.
`G11.2`	Hereditary spastic paraplegia	Some hereditary neurodegenerative disorders overlap clinically and prompt genetic testing including repeat-expansion panels.
`G11.4`	Cerebellar ataxia, unspecified	Symptom-based diagnosis prompting genetic evaluation for repeat expansion disorders such as ATXN10.
`R27.0`	Ataxia, unspecified	Presents with gait instability and coordination issues leading to targeted genetic testing.
`Z15.01`	Genetic susceptibility to neurodegenerative disease	Used when there is family history or carrier screening context prompting targeted ATXN10 testing.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`81183`	Detection of expanded repeat sequences in the ataxin 10 gene (ATXN10) — technical lab test performed to detect abnormal alleles involving expanded sequences.	Primary code describing the molecular test for ATXN10 repeat expansions.
`81479`	Unlisted molecular pathology procedure	Used when a specific CPT code is not available for a particular molecular test or when additional unique testing is performed not covered by existing codes.
`81225`	Huntington disease (HTT) gene analysis for CAG repeat expansion	Related hereditary ataxia/repeat-expansion testing workflow; laboratories performing repeat-primed PCR methods may run panels including multiple repeat-expansion assays.
`81243`	Myotonic dystrophy type 1 (DMPK) gene analysis for CTG repeat expansion	Commonly performed in the same molecular lab environment and may be ordered as part of differential diagnosis for neuromuscular/ataxia presentations.
`80500`	Esoteric pathology consultation or molecular pathology technical assistance (example of adjunct billing where applicable)	May be billed when additional professional consultation or specialized testing support is documented and billable per payer policy.

OpenPayer

Summary & Overview

CPT 81183: ATXN10 Expanded Allele Detection