Summary & Overview
CPT 81312: PABPN1 Gene Expansion Detection
CPT code 81312 covers a molecular diagnostic laboratory procedure to detect sequence changes and expanded alleles in the poly[A] binding protein nuclear 1 gene (PABPN1). Tests for PABPN1 expansions are used in diagnosis and confirmation of hereditary conditions characterized by pathogenic repeat expansions; as such, this code supports genetic confirmation that can affect clinical management and eligibility for targeted services. Nationally, genetic testing codes like CPT 81312 are important for laboratory reimbursement, clinical pathway integration, and ensuring access to confirmatory genetic diagnostics.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code’s clinical purpose, typical sites of service, and what to expect in payer coverage patterns. The publication outlines benchmarks for utilization and reimbursement context, notes recent policy and coding considerations relevant to molecular diagnostic assays, and summarizes clinical context for ordering providers and laboratories. Data not available in the input for specific payers’ coverage policies, reimbursement rates, associated taxonomies, and ICD-10 pairings are noted where applicable.
Billing Code Overview
CPT code 81312 describes a laboratory test that detects sequence changes in the poly[A] binding protein nuclear 1 gene (PABPN1), typically to identify abnormal alleles with expanded sequences. This test is a molecular diagnostic assay performed by a laboratory analyst and reports the presence or absence of pathogenic expansions in the targeted gene.
Service Type: Molecular diagnostic testing (genetic sequencing / expansion detection)
Typical Site of Service: Clinical laboratory / reference molecular diagnostics laboratory
Clinical & Coding Specifications
Clinical Context
A 48-year-old patient presents to a neuromuscular clinic with progressive ptosis, dysphagia, and slowly progressive proximal limb weakness that began in mid-adulthood and a family history suggestive of autosomal dominant inheritance. The neurologist orders molecular testing to detect an expanded trinucleotide repeat or other pathogenic variant in the poly(A) binding protein nuclear 1 gene (PABPN1) to confirm a suspected diagnosis of oculopharyngeal muscular dystrophy (OPMD). The clinical workflow includes pre-test genetic counseling, written informed consent, collection of a blood specimen in an EDTA tube, laboratory accessioning, DNA extraction, and a targeted molecular assay (fragment analysis, PCR sizing, or sequence analysis) performed by a molecular diagnostics laboratory. The lab analyst performs the technical testing under CPT 81312, reports allele sizing and interpretation, and the result is routed to the ordering neurologist or geneticist for post-test counseling. Typical site of service is an outpatient neurology or genetic clinic with testing performed in a clinical molecular diagnostics laboratory (reference or hospital-based).
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when only the professional interpretation/reporting portion of the test is billed separately from the technical component. |