Summary & Overview

CPT 0120U: Lymph3Cx Lymphoma Molecular Subtyping Assay

CPT code 0120U denotes the Lymph3Cx Lymphoma Molecular Subtyping Assay, a Proprietary Laboratory Analyses (PLA) code for a Mayo Clinic laboratory-developed molecular test that sequences 58 genes from preserved biopsy tissue and integrates clinical data to evaluate the likelihood of primary mediastinal B–cell lymphoma (PMBCL) versus diffuse large B–cell lymphoma (DLBCL). This code captures a complex, high-specificity diagnostic service that informs lymphoma classification and downstream treatment decisions, making it nationally relevant as precision oncology testing expands.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise national overview of coverage and reimbursement context for this PLA molecular assay, clinical utility and indication context for PMBCL and DLBCL subtyping, typical billing and site-of-service considerations, and an outline of available benchmarks and policy updates where applicable. Data not available in the input is noted where gaps exist.

This publication is intended to inform coding, policy, and payer-facing stakeholders about the clinical intent and billing classification of CPT code 0120U, helping users understand where the assay fits within molecular diagnostics and oncology service lines at a national level.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare0120UCPTProprietary Laboratory AnalysesMolecular DiagnosticsLymphomaLaboratory-Developed TestOncologyBiopsy Tissue Testing

Billing Code Overview

CPT code 0120U is a Proprietary Laboratory Analyses (PLA) code for the Lymph3Cx Lymphoma Molecular Subtyping Assay, a Mayo Clinic Laboratory–Developed Test. The assay is performed on a preserved biopsy tissue specimen and measures and sequences 58 genes, combining molecular results with patient data to assess the likelihood of primary mediastinal B–cell lymphoma (PMBCL) versus diffuse large B–cell lymphoma (DLBCL).

Service type: Molecular diagnostic laboratory testing (proprietary PLA; laboratory-developed test)
Typical site of service: Clinical molecular pathology laboratory or specialized diagnostic laboratory processing preserved biopsy tissue specimens

Clinical & Coding Specifications

Clinical Context

A 62-year-old patient presents with a rapidly enlarging mediastinal mass and systemic B symptoms (fever, night sweats, weight loss). A core needle biopsy of the mediastinal mass is performed and preserved in formalin; histopathology suggests high-grade B-cell lymphoma but cannot definitively distinguish primary mediastinal B‑cell lymphoma (PMBCL) from diffuse large B‑cell lymphoma (DLBCL). The treating hematologist-oncologist orders the Lymph3Cx Lymphoma Molecular Subtyping Assay (reportable with 0120U) to analyze a preserved biopsy tissue specimen. The assay sequences 58 genes and integrates clinical variables to provide a molecular subtype probability that helps guide therapeutic selection and prognostic counseling.

Typical clinical workflow:

Initial evaluation by oncology with history, physical exam, imaging (CT/PET), and biopsy.
Pathology performs histology and immunophenotyping; if lymphoma subtype remains uncertain, the pathologist or oncologist requests the Lymph3Cx assay.
The preserved tissue block or unstained slides are sent to the Mayo Clinic laboratory with appropriate requisition and clinical information.
Mayo Clinic performs the PLA test, sequences the specified gene panel, integrates patient data, and returns a molecular subtyping report to the ordering provider.
The oncology team reviews results alongside pathology and imaging to finalize diagnosis and select targeted chemotherapy or immunotherapy regimens.

Coding Specifications

`11`	Service performed by the reporting physician	Use when the billing clinician is the primary physician who ordered and interpreted the test report.
`26`	Professional component	Use when billing only the professional interpretation component separate from the technical laboratory processing if applicable.
`TC`	Technical component	Use when billing only the technical component (laboratory processing and sequencing) without professional interpretation.
`22`	Increased procedural services	Use when additional work or complexity beyond typical assay processing is documented and meets payer policy for an unlisted add-on modifier.
`53`	Discontinued procedure	Rarely used; apply if specimen processing was begun but testing was discontinued and documentation supports medical necessity.
`52`	Reduced services	Use when a reduced or partial test was performed compared with the full-scope assay and documentation explains limitations.
`80`	Assistant surgeon	Not typically applicable to lab tests; included only if surgical assistant role is billed in a bundled surgical episode related to obtaining the specimen.
`62`	Two surgeons	Not typically applicable to the lab assay; can apply if multiple surgical providers bill for a specimen collection procedure.
`AD`	Medical supervision by a physician, more than four hours	Use when prolonged physician supervision for specimen collection, handling, or coordination is documented per payer rules.
`QK`	Medical direction of two, three, or four technicians/technologists	Use when the physician directs multiple lab technologists during complex testing workflows as defined by CPT guidance.
`QX`	Service performed by a qualified nonphysician practitioner	Use when a qualified nonphysician bills for portions of specimen collection or ordering under their scope.
`QY`	Attending physician of record or other physician directing the lab test	Use where payers recognize this modifier for supervision/ direction roles per laboratory rules.
`23`	Unusual anesthesia	Not typically applicable to this assay; included only if anesthesia was required for biopsy collection in an unusual situation.
`78`	Unplanned return to the operating/procedure room	Use only when there is an unexpected re-operation related to specimen collection; not routine for the assay.

Taxonomy Code	Specialty	Notes
`207RH0000X`	Hematology & Oncology	Ordering and interpreting clinicians who manage lymphoma diagnoses and direct therapy.
`208000000X`	Pathology	Surgical and anatomic pathologists who select and coordinate molecular testing from tissue specimens.
`363L00000X`	Clinical Laboratory & Pathology	Clinical laboratory directors and molecular diagnostic laboratory specialists overseeing assay performance.
`207K00000X`	Medical Oncology	Medical oncologists treating lymphoma who use molecular subtype information to guide systemic therapy.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C83.3`	Diffuse large B-cell lymphoma (DLBCL)	Primary diagnosis for which molecular subtyping with `0120U` helps distinguish DLBCL from PMBCL and informs prognosis and therapy.
`C84.6`	Primary mediastinal (thymic) large B-cell lymphoma	Specific target diagnosis for the assay; `0120U` estimates likelihood of PMBCL versus other DLBCL subtypes.
`C85.9`	Non-Hodgkin lymphoma, unspecified	Used when initial lymphoma diagnosis is pending subtype confirmation; molecular assay clarifies classification.
`R91.8`	Other nonspecific abnormal finding of lung field	May represent incidental imaging finding leading to biopsy and subsequent molecular testing for lymphoma.
`D76.2`	Lymphocytosis	Laboratory finding that can accompany lymphoproliferative disorders and prompt further diagnostic workup including molecular assays.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`88305`	Level IV surgical pathology, gross and microscopic examination	Performed on biopsy tissue to establish morphology; often precedes molecular testing and provides material selection for `0120U`.
`88342`	Immunohistochemistry, each antibody stain (specify number billed)	Used to characterize lineage and marker expression (e.g., CD20, CD30) that complements molecular subtyping provided by `0120U`.
`81479`	Unlisted molecular pathology procedure	Occasionally used for assays not otherwise coded; `0120U` replaces the need for unlisted coding when the Lymph3Cx test is used.
`88172`	Flow cytometry, cell marker-based immunophenotyping	May be performed on fresh specimens or aspirates to define immunophenotype in lymphoma workup prior to ordering `0120U`.
`88312`	Special staining, each stain procedure	Ancillary stains that can support lymphoma classification and help determine the need for molecular subtyping.