Summary & Overview
CPT 84233: Estrogen Receptor Assay on Tumor Tissue
CPT code 84233 identifies an estrogen receptor assay (ERA) performed on tumor tissue to detect estrogen receptor proteins that guide cancer treatment decisions. This laboratory pathology test is clinically important for breast cancer management because the presence or absence of estrogen receptors directly affects systemic therapy selection, including endocrine therapy eligibility. Nationally, ERA testing is a routine component of tumor characterization and influences clinical pathways, quality reporting, and laboratory billing patterns.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. The publication outlines how CPT code 84233 is used in clinical practice and billing, and summarizes typical coverage considerations among major payers.
Readers will learn the clinical context of the assay, the typical sites of service where the test is performed, and what operational stakeholders should expect when encountering CPT code 84233 on claims. The piece also describes common analytic and documentation considerations relevant to laboratories and pathology services. Data not available in the input is identified where applicable.
Billing Code Overview
CPT code 84233 describes an estrogen receptor assay (ERA) performed on tumor tissue, most commonly breast tissue. The test detects estrogen receptors, proteins that bind the hormone estrogen and help determine tumor hormone sensitivity. Results commonly inform systemic therapy decisions, including the use of endocrine therapies.
Service type: Laboratory — tumor marker / receptor assay
Typical site of service: Clinical laboratory or hospital-based pathology/laboratory service, using tissue obtained from surgical pathology or biopsy specimens.
Clinical & Coding Specifications
Clinical Context
A 58-year-old female presents after a core needle biopsy of a suspicious breast mass identified on mammography and ultrasound. The pathology report confirms invasive ductal carcinoma; the oncology team requests an estrogen receptor assay to determine tumor hormone receptor status and guide systemic therapy decisions. The specimen is submitted to the pathology laboratory; a histotechnologist prepares formalin-fixed, paraffin-embedded tissue sections and the lab analyst performs an estrogen receptor assay (84233) using immunohistochemistry or other validated assay methods. Results are interpreted by a pathologist and entered into the pathology report; positive estrogen receptor status supports endocrine therapy, while negative status influences chemotherapy planning. Typical workflow steps include specimen accessioning, tissue processing, assay performance, pathologist interpretation, and reporting. Typical site of service is a hospital outpatient laboratory or independent pathology laboratory associated with a breast surgery or oncology clinic.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only the pathologist's interpretation (professional component) separate from the technical lab work |