Summary & Overview
CPT 0491U: CellSearch ER Circulating Tumor Cell (CTC–ER) Test
CPT code 0491U designates the CellSearch® ER Circulating Tumor Cell (CTC–ER) Test, a Proprietary Laboratory Analyses (PLA) code that applies to a single manufacturer-specific assay from Menarini Silicon Biosystems Inc. The assay isolates circulating tumor cells from blood and characterizes them using protein biomarkers to quantify estrogen receptor (ER) expression, offering clinicians a noninvasive option to assess tumor biology. Nationally, PLA codes like 0491U matter because they identify unique, proprietary diagnostics with implications for test access, single-source pricing, and coverage determinations across payers.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of the clinical purpose of the test, the expected site(s) of service, and the reporting context for a PLA code. The publication outlines payer coverage considerations, common billing modifiers, and the clinical scenarios in which a circulating tumor cell ER assay is relevant.
This summary prepares clinicians, billing staff, and policy analysts to understand how CPT code 0491U is used, the service it represents, and the areas where payers commonly focus review and coverage policy. Data not available in the input will be noted where applicable in detailed sections.
Billing Code Overview
CPT code 0491U is a Proprietary Laboratory Analyses (PLA) code that applies specifically to the CellSearch® ER Circulating Tumor Cell (CTC–ER) Test from Menarini Silicon Biosystems Inc. The test selects and analyzes circulating tumor cells (CTCs) from a blood sample to characterize tumor cells using targeted protein biomarkers and to quantify estrogen receptor (ER) expression.
-
Service type: Laboratory diagnostic test using circulating tumor cell selection and biomarker analysis
-
Typical site of service: Clinical laboratory or specialty diagnostic laboratory (blood draw typically performed in an outpatient clinic or phlebotomy setting prior to lab processing)
Clinical & Coding Specifications
Clinical Context
A 58-year-old woman with a history of estrogen receptor–positive (ER+) metastatic breast cancer is undergoing systemic treatment and serial monitoring. The oncology team orders the CellSearch® ER Circulating Tumor Cell (CTC–ER) Test to quantify circulating tumor cells in a peripheral blood sample and to characterize ER protein expression on captured CTCs. Peripheral venipuncture is performed in an outpatient oncology infusion center or clinical laboratory; the blood specimen is processed by the specialized laboratory using the proprietary CellSearch® platform. Results are used to assess tumor biology, evaluate treatment response or resistance to endocrine therapy, and inform discussions about potential changes in systemic therapy. The typical site of service is an outpatient clinical laboratory or hospital outpatient lab associated with an oncology clinic. Specimen collection, handling, and shipment follow the manufacturer and laboratory protocols; testing is performed solely by the lab holding the PLA test. Billing uses the Proprietary Laboratory Analyses code 0491U specifically for the CellSearch® ER CTC Test, with specimen handling and any separate pathology professional or technical components reported with appropriate modifiers when applicable.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | Use when reporting only the professional interpretation component separate from the technical component if applicable and allowed by the performing laboratory. |