Summary & Overview
CPT 81342: T‑cell Receptor Gamma Clonality Assay
CPT code 81342 identifies a molecular diagnostic laboratory test that detects abnormal clonal T‑cell populations by assessing the T‑cell receptor, gamma (TRG@) locus. This test has clinical relevance for the diagnosis and monitoring of certain leukemias and lymphomas, where detection of clonality can aid diagnostic classification and treatment planning. Nationally, molecular clonality testing is a growing component of hematopathology services due to advances in targeted therapies and precision diagnostics.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the clinical purpose of the test, typical sites of service, and the payer landscape. The publication summarizes common billing and coding considerations, typical modifiers observed, and related service-line context. It also provides benchmarks and policy-relevant updates where available, and situates CPT code 81342 within molecular pathology service delivery. The content is designed to inform laboratory managers, billing professionals, and policy analysts about how this code is used and reimbursed across major payers. Data not available in the input is noted where applicable.
Billing Code Overview
CPT code 81342 describes a laboratory molecular diagnostic test that detects abnormal clonal T‑cell populations by analyzing the T‑cell receptor, gamma (TRG@) locus. The assay is performed by a laboratory analyst and is used to identify clonal T‑cell populations that may be indicative of certain leukemias and lymphomas.
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Service type: Molecular/pathology diagnostic test (laboratory procedure)
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Typical site of service: Clinical laboratory or hospital laboratory performing molecular diagnostic testing
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Clinical & Coding Specifications
Clinical Context
A 62-year-old male with progressive lymphadenopathy and unexplained cytopenias is referred to hematology after peripheral blood smear and flow cytometry suggest a T-cell lymphoproliferative disorder. A core needle biopsy of an enlarged lymph node and a peripheral blood specimen are submitted to the molecular laboratory for clonality testing. The laboratory performs a 81342 assay to detect clonal T‑cell receptor gamma (TRG@) gene rearrangements to help distinguish reactive T‑cell expansions from malignant clonal T‑cell populations. Results are integrated with histopathology, immunophenotyping, and clinical findings and reported to the ordering hematologist/oncologist.
Typical workflow steps:
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Specimen receipt and accessioning (lymph node tissue, bone marrow aspirate, or peripheral blood).
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DNA extraction and quality assessment.
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PCR amplification and fragment analysis or sequencing of TRG@ locus per validated laboratory protocol.
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Interpretation for monoclonal versus polyclonal T‑cell populations and reporting of the technical result (
81342) with correlation notes for the ordering clinician.
Typical site of service: hospital clinical molecular pathology laboratory, independent reference molecular laboratory, or academic medical center molecular diagnostics lab.