Summary & Overview
CPT 82378: Carcinoembryonic Antigen (CEA) Quantitative Assay
CPT code 82378 denotes a quantitative laboratory assay for carcinoembryonic antigen (CEA), a tumor marker most commonly used to monitor patients with colon cancer and to follow other malignancies. As a widely ordered laboratory service, CEA testing plays a role in post-treatment surveillance and in assessing disease progression or recurrence, making accurate coding and coverage understanding important for clinical and billing workflows nationwide. Key payers in typical coverage analyses include Aetna, Blue Cross Blue Shield, Cigna Health, United Healthcare, and Medicare. This publication provides a concise national overview of CPT code 82378, presenting clinical context, common sites of service, and the coverage environment. Readers will find practical benchmarks for utilization and reimbursement patterns, summaries of payer policies that affect claim processing, and clinical notes on appropriate use and testing contexts. The content is intended to help billing managers, laboratory directors, and healthcare policy stakeholders understand where 82378 fits in laboratory service lines, typical clinical indications, and the payer landscape that influences claims and utilization at a national level. Data not available in the input for certain payer-specific policy details or associated diagnosis codes is noted where applicable.
Billing Code Overview
CPT code 82378 describes a laboratory test that measures the quantity of carcinoembryonic antigen (CEA) in blood or other bodily fluids. The test is performed by a clinical laboratory technologist or analyst and is primarily used to monitor patients with colon cancer and to assist in monitoring other types of cancer.
Service type: Laboratory — Quantitative tumor marker assay
Typical site of service: Clinical laboratory or hospital outpatient laboratory, with specimens collected in physician offices, outpatient clinics, or inpatient settings as appropriate.
Clinical & Coding Specifications
Clinical Context
A 62-year-old patient with a history of stage II colorectal adenocarcinoma presents for routine surveillance following surgical resection and adjuvant chemotherapy. The treating oncologist orders a serum carcinoembryonic antigen test to monitor for biochemical evidence of disease recurrence. In the clinical workflow, a phlebotomy technician draws blood in an outpatient oncology clinic or hospital outpatient laboratory; the sample is sent to the clinical laboratory. A laboratory analyst performs the quantitative immunoassay for carcinoembryonic antigen and reports the numeric result and reference range to the ordering clinician. Results are reviewed during follow-up visits and used alongside imaging and clinical assessment to guide surveillance decisions.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
26 | Professional component | When billing only for the laboratory professional interpretation component (rare for automated CEA assays). |
90 | Reference (outside) laboratory | When testing is performed by an outside certified reference laboratory and billing needs to indicate external lab involvement. |