Summary & Overview
CPT 81343: PPP2R2B Repeat Expansion Detection, Molecular Diagnostic
CPT code 81343 identifies a molecular diagnostic laboratory test for detecting expanded sequence alleles in the PPP2R2B gene. This genetic test is used to identify abnormal repeat expansions that can underlie specific neurogenetic disorders. As a specialized molecular assay performed by clinical and reference laboratories, the code captures the technical component of genetic testing workflows and is relevant for payers and providers involved in diagnostic evaluation of suspected hereditary neurologic conditions.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The analysis covers reimbursement and coverage considerations across those payers, typical sites where the service is delivered, and the clinical context in which testing is ordered.
Readers will find a concise explanation of what the code represents, the clinical indications for PPP2R2B repeat-expansion testing, payer coverage patterns, common billing modifiers and administrative considerations, and benchmarking information where available. The publication also summarizes coding relationships and points of operational importance for laboratories and billing staff. Data not available in the input are noted where applicable.
Billing Code Overview
CPT code 81343 describes a laboratory molecular diagnostic test that detects expanded sequence alleles in the protein phosphatase 2 regulatory subunit Bbeta (PPP2R2B) gene. The service involves laboratory technical work to identify abnormal repeat expansions in the PPP2R2B gene sequence that are associated with certain neurogenetic conditions.
Service type: Molecular diagnostic / Genetic testing (technical component)
Typical site of service: Clinical laboratory or reference genetic testing laboratory
Data not available in the input.
Clinical & Coding Specifications
Clinical Context
A patient is referred to a molecular diagnostics laboratory for targeted genetic testing to evaluate for an expanded trinucleotide repeat mutation in the PPP2R2B gene (protein phosphatase 2 regulatory subunit Bbeta) when there is clinical suspicion for spinocerebellar ataxia type 12 (SCA12) or related hereditary ataxia. Typical patients are adults presenting with progressive gait instability, limb ataxia, dysarthria, tremor, or a family history consistent with an autosomal dominant ataxia.
The clinical workflow begins with a neurology or genetic counseling consultation documenting the clinical indication and family history. After informed consent, a blood sample (EDTA tube) is collected and sent to a cytogenetics/molecular genetics laboratory. The laboratory performs targeted testing to detect expanded CAG/CTG repeat sequences or other expanded sequences in the PPP2R2B gene using polymerase chain reaction (PCR) sizing, fragment analysis, and when necessary Southern blot or triplet-primed PCR to resolve large expansions. Results are interpreted by a clinical laboratory geneticist and returned to the ordering clinician, including allele sizes, whether an expanded pathogenic allele is detected, and implications for diagnosis, prognosis, and family testing. Typical site of service is an outpatient molecular diagnostics laboratory with specimen drawn in an ambulatory clinic, neurology practice, or genetic counseling office. Billing for the technical laboratory testing component corresponds to the molecular test described by 81343.
Coding Specifications
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