Summary & Overview
CPT 81271: Huntingtin (HTT) Gene Expanded Allele Detection
CPT code 81271 identifies a molecular diagnostic laboratory assay that detects expanded alleles in the huntingtin gene (HTT) by measuring allele size. This test is clinically important for diagnosing Huntington disease and for genetic counseling, influencing care pathways for patients with neurodegenerative symptoms or a relevant family history. Nationally, availability and coverage policies for HTT testing affect access to definitive diagnosis and downstream services such as specialty neurology referral and genetic counseling.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication outlines payer coverage patterns, typical reimbursement considerations, and clinical context for ordering the test. Readers will find concise benchmarks on payment and coverage approaches, a summary of typical clinical indications and testing workflows, and a review of relevant policy considerations that influence laboratory utilization and access. Where specific payer or coding details are not provided in the input, the text notes that data is not available in the input. The content is intended for national audiences including payers, laboratory directors, policy analysts, and clinicians involved in genetic testing pathways.
Billing Code Overview
CPT code 81271 describes a laboratory test that detects changes in the huntingtin gene (HTT), typically identifying abnormal alleles with expanded CAG repeat sequences by allele size. This service is a molecular genetic diagnostic test used to confirm or characterize Huntington disease–related genetic expansions.
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Service type: Genetic testing / molecular diagnostic laboratory service
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Typical site of service: Clinical molecular laboratory or specialized genetic testing laboratory
Clinical & Coding Specifications
Clinical Context
A patient with a family history of Huntington disease or who presents with progressive chorea, cognitive decline, or psychiatric changes is referred for molecular diagnostic testing of the huntingtin gene. Typically the patient is seen in a neurology or genetics clinic where the clinician documents signs and symptoms, obtains informed consent for genetic testing, and collects a peripheral blood specimen. The specimen is sent to a molecular genetics laboratory where a clinical laboratory scientist performs fragment analysis or triplet-primed PCR to determine CAG repeat length in the HTT gene. Results classify alleles as normal, intermediate, reduced penetrance, or pathogenic expanded repeats and are used for diagnostic confirmation, predictive testing for at-risk adults, or prenatal/perinatal counseling when appropriate. Typical site of service is an outpatient clinic for specimen collection and a reference or hospital molecular diagnostics laboratory for testing. Common payors include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, BUCA, and Medicare for medically indicated diagnostic or predictive testing.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier reported | Default when no modifier applies |