Summary & Overview
CPT 0177U: PIK3CA PCR Assay for Plasma (Liquid Biopsy)
CPT code 0177U identifies a proprietary molecular diagnostic assay — the therascreen® PIK3CA RGQ PCR Kit from QIAGEN — used to detect 11 specific PIK3CA mutations in blood plasma via quantitative PCR. As a PLA code, 0177U applies only to this unique manufacturer test and is used to distinguish the assay for reporting, coverage, and reimbursement considerations. Nationally, codes like 0177U matter for precision oncology pathways, claims adjudication, and lab reporting transparency.
Key payers in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code's clinical purpose and service settings, payer coverage considerations and common modifiers used in claims, and context on how PLA codes function within molecular diagnostic billing. The publication also summarizes relevant benchmarking and policy implications for proprietary lab tests, including coding precision and the role of PLA codes in tracking manufacturer‑specific assays.
This summary is intended to provide clinicians, laboratory billing staff, and policy analysts with a clear, national‑level reference for CPT code 0177U, its clinical application, and the payer landscape relevant to molecular oncology testing.
Billing Code Overview
CPT code 0177U is a Proprietary Laboratory Analyses (PLA) code for the therascreen® PIK3CA RGQ PCR Kit from QIAGEN. The code is reported for a real‑time (quantitative) polymerase chain reaction (PCR) assay that detects 11 mutations in the phosphatidylinositol 3‑kinase catalytic subunit alpha (PIK3CA) gene in blood plasma. This represents a manufacturer‑specific liquid biopsy test targeting PIK3CA variants.
Service type: Molecular diagnostic testing using quantitative PCR to detect specific PIK3CA mutations in circulating cell‑free DNA.
Typical site of service: Clinical or reference laboratory processing with specimens collected in outpatient phlebotomy or clinic settings and analyzed in a laboratory equipped for molecular diagnostics.
Clinical & Coding Specifications
Clinical Context
A 62-year-old woman with hormone receptor–positive, HER2-negative metastatic breast cancer on endocrine therapy develops progressive disease with new visceral metastases. Her oncologist orders a plasma-based circulating tumor DNA (ctDNA) assay using the therascreen® PIK3CA RGQ PCR Kit to detect activating PIK3CA mutations that may predict benefit from PI3K inhibitor therapy. A peripheral blood draw is performed in the outpatient oncology clinic; the specimen is labeled and shipped to the performing laboratory under chain-of-custody and temperature-controlled conditions. The laboratory performs real-time quantitative PCR to evaluate 11 predefined PIK3CA hotspot mutations and reports a qualitative result (mutation detected / not detected) with analytic comments and assay limitations. The result is returned to the oncologist and entered into the electronic medical record to inform systemic therapy selection and clinical trial eligibility decisions.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | Default - No modifier | Use when no specific modifier applies to the service. |
11 | Office or outpatient service furnished personally by the reporting physician | Use when the ordering physician also personally performs the specimen collection or direct patient encounter tied to the test. |
26 | Professional component | Use if billing separates the professional interpretation component from the technical laboratory component (rare for PLA codes). |
TC | Technical component | Use when billing only the laboratory technical component (instrumentation, reagents, personnel). |
52 | Reduced services | Use when the lab performs a reduced or limited version of the test relative to the full procedure. |
59 | Data not available in the input. | |
62 | Two surgeons/physicians | Use when two qualified physicians share responsibility for the patient’s care related to specimen procurement (e.g., interventional radiology and oncology). |
78 | Unplanned return to the operating/procedure room by the same physician following initial procedure | Use if an unexpected procedural complication requires a repeat invasive specimen collection during the same operative session. |
80 | Assistant surgeon | Use when an assistant surgeon participates in obtaining a tissue specimen that leads to the test when coding allows. |
QK | Medical direction of two or more qualified health care professionals | Use if the physician directed a team performing specimen collection under medical direction rules. |
QX | CRNA service: personally performed | Use when a certified registered nurse anesthetist personally performs anesthesia services related to a specimen acquisition procedure. |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
207RC0000X | Medical Oncology | Order and interpretation of tumor mutation testing to guide systemic therapy. |
207L00000X | Hematology/Oncology | Management of patients with metastatic solid tumors and coordination of molecular testing. |
208000000X | Pathology | Oversight of laboratory testing, result validation, and reporting of molecular assay findings. |
1744P0800X | Interventional Radiology | Image-guided specimen procurement when tissue-based testing is required; may coordinate with plasma testing. |
363A00000X | Phlebotomy/Laboratory Technician | Specimen collection and processing for plasma ctDNA assays. |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
C50.911 | Malignant neoplasm of unspecified site of right female breast | Common primary diagnosis for ordering PIK3CA testing to guide targeted therapy in metastatic breast cancer. |
C50.912 | Malignant neoplasm of unspecified site of left female breast | Same clinical relevance for left-sided breast primary. |
C79.51 | Secondary malignant neoplasm of bone | Indicates metastatic disease where ctDNA testing may be used to identify actionable mutations. |
C78.7 | Secondary malignant neoplasm of liver and intrahepatic bile duct | Visceral metastases often prompt molecular testing to guide systemic therapy. |
Z85.3 | Personal history of malignant neoplasm of breast | May be present in patients with recurrent or metastatic disease undergoing mutation testing. |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
36415 | Collection of venous blood by venipuncture | Frequently performed immediately prior to 0177U to obtain plasma for the ctDNA PCR assay. |
99000 | Handling and/or conveyance of specimen for transfer from the office to a laboratory (this is illustrative; specific local codes may vary) | Often used for specimen shipping/handling when sending plasma to a reference lab performing 0177U. |
88360 | Immunohistochemistry or special stains, per specimen; technical and professional components combined (example ancillary pathology testing) | May be performed on tissue specimens in parallel with plasma testing when tumor tissue is available to confirm mutation status. |
81479 | Unlisted molecular pathology procedure | Used when a molecular test lacks a specific CPT code; historically used prior to availability of a PLA code like 0177U. |
99070 | Supplies and materials (e.g., clinical laboratory supplies) provided by the physician over and above those usually included with the office visit | May apply when special collection kits or shipping materials are supplied for the plasma assay. |