Summary & Overview
CPT 81321: PTEN Full Gene Sequencing, Laboratory Technical Component
CPT code 81321 represents full-gene sequencing of the PTEN (phosphatase and tensin homolog) gene performed by a laboratory technical analyst. Nationally, comprehensive PTEN sequencing is clinically important for diagnosing hereditary cancer syndromes and certain developmental disorders, and it supports treatment planning, genetic counseling, and cascade testing.
Key payers discussed in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of coverage considerations, typical sites of service, and the clinical contexts in which PTEN sequencing is ordered. The publication also summarizes available national benchmarks for utilization where present, common payer policies and prior authorization themes, and how CPT code 81321 fits into broader molecular diagnostics workflows.
This summary provides clinicians, laboratory managers, and billing staff with concise context for CPT code 81321, highlighting where the service is delivered, why full-gene PTEN sequencing matters clinically, and what types of policy and billing topics to expect in the full publication. Data not available in the input will be noted where applicable.
Billing Code Overview
CPT code 81321 describes a molecular diagnostic laboratory test that performs analysis of the entire coding sequence of the PTEN (phosphatase and tensin homolog) gene. The service is a technical laboratory procedure in which a lab analyst processes and analyzes DNA to detect sequence variants across the PTEN gene.
Service type: Molecular diagnostic — full gene sequencing
Typical site of service: Clinical laboratory or reference molecular diagnostics laboratory
Clinical & Coding Specifications
Clinical Context
A 34-year-old patient with a personal and family history of early-onset breast cancer is referred to a genetics clinic for hereditary cancer risk assessment. The clinician orders comprehensive sequencing of the PTEN gene to evaluate for PTEN hamartoma tumor syndrome (including Cowden syndrome) because the patient meets clinical criteria (multiple hamartomas, personal thyroid lesion, and macrocephaly) and there is concern for pathogenic germline variants that influence surveillance and management. A phlebotomy draw is performed in the outpatient laboratory; the specimen is sent to a molecular diagnostics laboratory. A molecular laboratory technologist performs DNA extraction, library preparation, sequencing, and bioinformatic analysis across the entire coding region and relevant intronic boundaries of the PTEN gene. The laboratory issues a report describing detected sequence variants, variant classification (pathogenic, likely pathogenic, VUS, likely benign, benign), and recommended follow-up testing if applicable. Billing for the technical component of full-gene sequencing is submitted using 81321 with the laboratory’s usual place of service code (typically outpatient laboratory or independent diagnostic testing facility). Typical providers involved include medical geneticists, genetic counselors, oncologists, endocrinologists, and laboratory molecular pathologists. Turnaround time for routine testing is often 2–4 weeks; urgent testing may use modifier QK/QX workflows when applicable for targeted rapid testing, though 81321 denotes full-gene analysis rather than targeted single-variant assays.
Coding Specifications
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