Summary & Overview
CPT 81285: FXN (Frataxin) Gene Repeat Characterization
CPT code 81285 designates a molecular laboratory procedure to characterize changes in the frataxin gene (FXN), most often used to identify nucleotide repeat expansions after an expanded allele is detected. This analysis is clinically important because characterization of FXN repeat length and sequence informs diagnosis, prognosis, and genetic counseling for conditions linked to frataxin abnormalities. Nationally, such specialized genetic testing is performed in clinical molecular laboratories and is relevant to neurology, genetics, and related specialties.
Key payers covered in this overview include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the clinical purpose and service setting of CPT code 81285, along with information on common billing modifiers and procedural context where available. The publication provides benchmarks and policy-oriented content including coverage patterns, coding considerations, and payer-specific policy summaries where data is available. It also outlines clinical context for ordering and interpreting FXN repeat characterization, typical laboratory workflow implications, and areas where policy updates or payer guidance commonly affect billing and reimbursement.
Where input data was not provided, this summary notes that specific payer policies, associated taxonomies, ICD-10 pairings, and related codes are not available in the input.
Billing Code Overview
CPT code 81285 describes a laboratory technical procedure to characterize sequence changes in the frataxin gene (FXN), typically performed to identify or confirm nucleotide repeat expansions after detection of an expanded allele size. The service focuses on molecular genetic analysis to determine the nature of FXN gene changes associated with clinical findings.
Service type: Molecular genetic testing / Laboratory technical procedure
Typical site of service: Clinical molecular laboratory
Data not available in the input for payers, associated taxonomies, ICD-10 diagnoses, and related codes.
Clinical & Coding Specifications
Clinical Context
A 28-year-old patient with progressive gait instability and family history of Friedreich ataxia is referred for molecular diagnostic testing. Initial screening by a laboratory or genetic counselor identified an expanded allele size in the frataxin gene (FXN) by a repeat-primed PCR or other screening assay. The laboratory then performs the technical characterization test to determine the exact GAA trinucleotide repeat number and to confirm zygosity, using methods such as Southern blot, long-range PCR, or triplet-repeat primed PCR followed by sizing. Specimen collection is typically a venous whole blood draw placed in EDTA and sent to a molecular diagnostics laboratory. The testing is performed in a clinical molecular genetics laboratory by a laboratory analyst/technologist with specialized equipment. Results are reported to the ordering clinician (neurologist, geneticist, or pediatric neurologist) and genetic counselor to inform diagnosis, prognosis, family counseling, and cascade testing strategies.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only the professional interpretation/reporting portion if separate from the technical lab work |
TC | Technical component |