Summary & Overview
CPT 0155U: PIK3CA PCR Kit for Breast Tumor Mutation Detection
CPT code 0155U designates a Proprietary Laboratory Analyses (PLA) molecular test — the therascreen® PIK3CA RGQ PCR Kit from QIAGEN — for detecting 11 PIK3CA mutations in breast tumor tissue. As a PLA code, 0155U applies uniquely to this specific manufacturer’s assay, which is used in oncologic molecular profiling to inform targeted treatment decisions for patients with breast cancer.
Key national payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna, UnitedHealthcare, and Medicare. Readers will find a concise overview of clinical context for PIK3CA testing, the coding and billing implications of a PLA CPT code, and what to expect from payer coverage patterns at a high level.
The publication provides benchmarks and policy-relevant details: an explanation of how PLA codes differ from general molecular CPT codes, typical sites of service and specimen types for billing, and common payer considerations for proprietary tests. It also outlines areas where data was not available in the input, such as specific payer policy language, reimbursement amounts, associated taxonomies, and ICD-10 mappings. The goal is to give clinicians, lab managers, and billing professionals a clear, national-level briefing on CPT code 0155U and its role in breast cancer molecular diagnostics.
Billing Code Overview
CPT code 0155U is a Proprietary Laboratory Analyses (PLA) code for the therascreen® PIK3CA RGQ PCR Kit from QIAGEN. The test is a real‑time quantitative PCR assay designed to detect 11 mutations in the phosphatidylinositol 3‑kinase catalytic subunit alpha (PIK3CA) gene in breast tumor tissue.
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Service type: Molecular diagnostic testing for PIK3CA mutation detection in tumor tissue
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Typical site of service: Clinical laboratory or pathology laboratory processing breast tumor tissue specimens
Data not available in the input.
Clinical & Coding Specifications
Clinical Context
A 58-year-old woman with hormone receptor–positive, HER2-negative advanced or metastatic breast cancer undergoes tumor genotyping to evaluate eligibility for targeted therapy directed at PIK3CA mutations. A formalin-fixed, paraffin-embedded (FFPE) breast tumor tissue block or unstained slides are submitted to the laboratory. The laboratory performs the therascreen® PIK3CA RGQ PCR Kit (report with CPT 0155U) to detect 11 activating PIK3CA mutations using real-time quantitative PCR. Results are returned to the treating oncologist and incorporated into therapeutic decision-making, such as consideration of PI3K inhibitors when a qualifying mutation is detected.
Workflow steps:
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Ordering: Oncologist orders tumor PIK3CA testing and records clinical indication and specimen type.
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Specimen collection and transport: Surgical pathology identifies and prepares FFPE tissue block or unstained slides and ships with appropriate documentation to the performing laboratory.
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Laboratory analysis: Molecular pathology performs extraction, PCR-based assay using the therascreen PIK3CA RGQ PCR Kit, interprets results, and issues a report noting detected mutations and assay limitations.
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Reporting and clinical use: Results are posted in the medical record and used by the oncology team to inform systemic therapy selection and eligibility for targeted agents or clinical trials.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only the professional interpretation component separate from the technical component. |
TC | Technical component | When billing only the technical component (laboratory processing and equipment) separate from the professional interpretation.
59 | Distinct procedural service (Note: not listed among provided modifiers) | Data not available in the input.
22 | Increased procedural services | When work required to perform or interpret the test is substantially greater than typical (use with documentation of extra effort and medical necessity).
52 | Reduced services | When the service is partially reduced or not completed as planned (for example, limited analysis due to inadequate specimen).
53 | Discontinued procedure | When testing is started but discontinued due to specimen unsuitability or preanalytic failure.
78 | Unplanned return to the operating/procedure room by the same physician following initial procedure (Note: rarely applicable to lab PLA codes) | Data not available in the input.
80 | Assistant surgeon (Note: not applicable to lab testing) | Data not available in the input.
QK | Medical direction of two, three, or four qualified health care professionals | When the physician performs medical direction of multiple qualified individuals in performing the testing process (rare for single-lab PLA).
QX | CRNA service: CRNA with medical direction by physician | Data not applicable to laboratory PLA codes.
QY | Medical direction of one certified registered nurse anesthetist (Note: not applicable) | Data not available in the input.
AD | Advanced beneficiary notice applicability (private payer usage varies) | When an advanced notice is applied per payer rules (local payer policy dependent).
AS | Physician assistant, nurse practitioner, or clinical nurse specialist services for assistant at surgery (not applicable to lab testing) | Data not available in the input.
CO | Staged or related procedure (payer-specific) | When ordered and billed under payer policies that require CO designation for related services (use per payer guidance).
| Taxonomy Code | Specialty | Notes |
|---|---|---|
207RG0100X | Hematopathology / Molecular Pathology | Molecular pathologists or clinical laboratory directors who interpret somatic mutation testing. |
207L00000X | Anatomic Pathology | Surgical pathologists who oversee tissue handling, selection of tumor blocks, and coordination with molecular testing.
207P00000X | Medical Oncology | Medical oncologists who order tumor genotyping to guide systemic therapy.
208D00000X | General Surgery / Surgical Oncology | Surgical oncologists who obtain tumor specimens and coordinate pathology submissions.
363LF0000X | Laboratory Technician / Clinical Laboratory | Laboratory professionals who perform technical components of molecular assays (note: taxonomy reflects laboratory practice specialties).
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
C50.912 | Malignant neoplasm of unspecified site of left female breast | Locoregional breast cancer tissue submitted for PIK3CA mutation testing to guide targeted therapy selection. |
C50.911 | Malignant neoplasm of unspecified site of right female breast | Tumor tissue from the right breast evaluated for actionable PIK3CA mutations.
C79.81 | Secondary malignant neoplasm of breast | Metastatic breast tumor tissue tested for somatic PIK3CA mutations to guide systemic therapy decisions.
Z85.3 | Personal history of malignant neoplasm of breast | Historical context where recurrent disease or new lesions prompt molecular testing of current tumor.
D05.90 | Lobular carcinoma in situ of unspecified breast | In select cases, when invasive disease is suspected or concurrent invasive components exist, molecular profiling may be considered.
C50.912 | Malignant neoplasm of left breast, unspecified (duplicate) | Duplicate entry omitted in interpretation; only listed once for coding clarity.
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
81507 | PIK3CA (e.g., genomic sequence analysis) | May represent alternative molecular testing for PIK3CA mutational analysis when different methodology or non-proprietary assays are used; used in the molecular workup of breast cancer. |
88342 | Immunohistochemistry, peroxidase-antiperoxidase, each antibody (per slide) | Performed on tumor tissue to determine hormone receptor or HER2 status prior to molecular testing and to select appropriate tumor blocks for molecular analysis.
88305 | Level IV surgical pathology, gross and microscopic examination | Applied when initial surgical pathology evaluation and block selection are performed before molecular testing; supports specimen documentation and triage for molecular assays.
0001U | (Example PLA code for another specific assay) | Data not available in the input.
0002U | (Example PLA code) | Data not available in the input.