CPT 0009U: DEPArray HER2 Tumor‑Cell Isolation with FISH Analysis

CPT code 0009U designates DEPArray™ HER2 by PacificDx, a Proprietary Laboratory Analyses (PLA) test that isolates tumor cells and performs fluorescence in situ hybridization (FISH) to report HER2 (ERBB2) gene amplification. The code captures a manufacturer‑specific laboratory service used in oncology diagnostics to guide targeted therapy decisions and treatment planning. Nationally, PLA codes like 0009U matter because they document proprietary assays with single‑source ownership and can affect coverage, coding consistency, and lab reimbursement policies.

Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of the clinical context for HER2 FISH testing, the service setting and workflow implications, and typical payer considerations. The publication outlines available benchmarks and policy elements related to proprietary laboratory analyses, notes common modifier usage where applicable, and highlights areas where payers often require documentation or prior authorization. The content is intended for billing professionals, laboratory directors, and policy analysts seeking a concise reference on the clinical purpose, billing classification, and payer landscape for CPT code 0009U. Data not available in the input for associated taxonomies, ICD‑10 diagnoses, and related codes are noted where applicable.

Billing Code Overview

CPT code 0009U is a Proprietary Laboratory Analyses (PLA) code for DEPArray™ HER2 by PacificDx. The code describes a tumor‑cell isolation procedure followed by fluorescence in situ hybridization (FISH) analysis of isolated tumor cells to determine HER2 (ERBB2) gene amplification status.

Service type: Laboratory test with tumor‑cell isolation and targeted FISH analysis

Typical site of service: Clinical laboratory or specialized pathology/molecular diagnostics laboratory

Clinical Context

A 58-year-old woman with a history of invasive breast carcinoma presents with a locally recurrent lesion after prior lumpectomy and adjuvant chemotherapy. The treating oncologist requires precise determination of HER2 (ERBB2) gene status from a small tissue sample and from tumor cells isolated from a heterogeneous specimen to guide targeted therapy decisions. A tissue or cytology specimen (core biopsy, fine-needle aspirate, or cell block) is submitted to a certified molecular laboratory. The laboratory performs the DEPArray™ tumor-cell isolation workflow to enrich for tumor cells, followed by fluorescence in situ hybridization (FISH) targeting HER2/ERBB2 to determine gene amplification status. The final report documents HER2 amplified, equivocal, or not amplified and is returned to the ordering oncologist for therapeutic planning. Typical site of service is an outpatient or hospital-based pathology/molecular laboratory; specimen collection occurs in an ambulatory clinic, imaging suite, or hospital procedure area.

Coding Specifications

Modifier	Description	When to Use
`TC`	Technical component	Use when billing only the laboratory technical component of the test if the performing lab separates technical/professional billing.
`26`

Taxonomy Code	Specialty	Notes
`207RG0100X`	Anatomic Pathology & Clinical Pathology	Pathologists who interpret FISH results and provide consultative reports.
`207RN0000X`	Molecular Genetic Pathology	Specialists who oversee molecular workflows including tumor-cell isolation and FISH.
`363A00000X`	Clinical Laboratory	Laboratory organizations performing the DEPArray™ isolation and FISH technical processing.
`208D00000X`	Medical Oncology	Ordering clinicians who request HER2 testing to guide therapy.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C50.911`	Malignant neoplasm of unspecified site of right female breast	Breast carcinoma is a primary indication for HER2 FISH testing to determine ERBB2 amplification status.
`C50.912`	Malignant neoplasm of unspecified site of left female breast	Same clinical relevance for left-sided breast tumors requiring HER2 assessment.
`C50.919`	Malignant neoplasm of unspecified site of unspecified female breast	Applicable when laterality is not specified; HER2 testing guides targeted therapy.
`C50.129`	Malignant neoplasm of upper-inner quadrant of left female breast	Site-specific breast cancers commonly undergo HER2 testing as part of biomarker panel.
`C79.81`	Secondary malignant neoplasm of breast	Metastatic involvement or recurrence may prompt tumor-cell isolation and HER2 testing to reassess amplification in metastatic tissue.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`88377`	Special stains including interpretation and report; each additive stain	May be performed on the specimen for ancillary histochemical staining prior to or alongside FISH in pathology workflow.
`88384`	Immunohistochemistry (IHC), per specimen; each antigen	IHC for HER2 protein expression is commonly performed before or concurrently with FISH to assess HER2 status.
`88367`	Morphometric analysis, tumor markers	Used when computerized image analysis complements FISH quantification in select cases.
`88271`	Flow cytometry, per specimen; single cell type	Alternative or complementary cell-based analyses; not specific to DEPArray™ but may be part of cellular characterization.
`88172`	Cytopathology, cell block, immunocytochemistry	Relevant when cytology specimens or cell blocks are processed before molecular testing and enrichment.

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Summary & Overview