Summary & Overview
CPT 81171: AFF2 (FMR2) Expanded-Sequence Detection
CPT code 81171 designates a laboratory technical procedure for detecting expanded-sequence changes in the AFF2 (FMR2/ALF) gene. This molecular diagnostic test identifies common abnormal expanded repeats that have clinical relevance in genetic evaluation. Nationwide, accurate reporting of this code supports clinical genetics workflows, laboratory billing consistency, and appropriate tracking of molecular testing utilization.
Major national payers commonly associated with coverage and reimbursement policies for molecular diagnostics include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Policies differ by carrier and by clinical indication, which affects prior authorization, medical necessity determinations, and coverage criteria.
Readers will find: an explanation of what CPT code 81171 represents; the clinical context for AFF2 (FMR2) expanded-sequence testing; common service settings where the technical component is performed; and a summary of typical payer considerations and documentation expectations. The publication also outlines benchmarking and policy update themes relevant to molecular diagnostic laboratory billing, and highlights the operational elements labs and billing teams monitor for accurate claim submission.
Data not available in the input: associated taxonomies, specific ICD-10 diagnosis codes, related CPT or HCPCS codes, and payer-specific policy details.
Billing Code Overview
CPT code 81171 describes a laboratory technical procedure to detect expanded sequence changes in the AFF2 (also known as FMR2 or ALF transcription elongation factor 2) gene. The test is used to identify common abnormal forms involving expanded nucleotide sequences in the gene, which can be relevant in genetic evaluation and diagnostic workups.
Service Type: Genetic testing — molecular diagnostic (technical component)
Typical Site of Service: Clinical molecular diagnostics laboratory or hospital laboratory (technical laboratory setting)
Clinical & Coding Specifications
Clinical Context
A male or female patient, often a child or young adult with a personal or family history suggestive of X‑linked intellectual disability, developmental delay, speech delay, or a history of fragile X–associated features, is referred for molecular testing of the AFF2 (FMR2/AFF2) gene to detect repeat expansions. The clinical workflow begins with a clinician (medical geneticist, pediatric neurologist, or genetic counselor) documenting indications and ordering the test. A phlebotomy or specimen-collection appointment is scheduled at an outpatient laboratory, hospital laboratory, or specialty genetic testing center. The specimen (usually whole blood in EDTA) is routed to a molecular diagnostics laboratory where a laboratory analyst performs the technical assay described by 81171 to detect expanded repeats or other common pathogenic changes in AFF2. Results are verified by laboratory personnel, a report is issued to the ordering provider, and genetic counseling is provided as indicated to discuss implications for diagnosis, family testing, and reproductive planning.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only the professional interpretation component if the lab separates technical and professional components. |