Summary & Overview

CPT 86304: Quantitative CA 125 Tumor Marker Assay

CPT code 86304 represents a quantitative laboratory assay for the cancer antigen CA 125, a tumor marker used in evaluating pancreatic cancer and other malignancies. As a laboratory diagnostic test, this code is important nationally for monitoring disease activity, guiding clinical decision-making, and informing treatment planning when CA 125 is clinically indicated. The test is typically performed in clinical or hospital laboratories on serum or body fluid samples and is billed under CPT coding standards.

Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code's clinical context, typical site of service, and service type. The publication also covers payer coverage patterns and benchmark considerations where available, recent policy or coding clarifications affecting lab services, and practical billing considerations such as common modifiers and service line impacts. Where specific input data is missing, the text notes that information is not available in the input. This national-level summary is designed to inform clinicians, billing staff, and policy analysts about the role of 86304 in diagnostic workflows and reimbursement frameworks.

AetnaBlue Cross Blue ShieldCigna HealthUnitedHealthcareMedicare86304CPTLaboratoryTumor MarkerCA125OncologyDiagnostic TestingSerum Assay

Billing Code Overview

CPT code 86304 describes a quantitative test for the cancer tumor antigen CA 125 performed on a patient's serum or other body fluid. The assay measures the concentration of CA 125, a tumor marker commonly evaluated in the context of pancreatic cancer and other malignancies.

Service type: Laboratory diagnostic test, tumor marker assay

Typical site of service: Clinical laboratory or hospital laboratory

Data not available in the input.

Clinical & Coding Specifications

Clinical Context

A 58-year-old female with a history of chronic pancreatitis presents with progressive abdominal pain and unintentional weight loss. The ordering clinician requests a serum tumor marker panel to assist with evaluation for possible pancreatic malignancy. A phlebotomist obtains a peripheral blood specimen which is transported to the clinical laboratory. The laboratory technologist performs a quantitative immunoassay for cancer antigen CA 125 using the serum sample. Results are reviewed and reported in the electronic medical record; elevated values are used alongside imaging, histopathology, and clinical findings to support diagnosis, staging, or disease monitoring.

Typical site of service: outpatient clinical laboratory or hospital laboratory. Service type: quantitative laboratory immunoassay for tumor marker measurement. Typical workflow: specimen collection, accessioning, centrifugation, analysis on validated instrumentation, result verification by a qualified laboratorian, and reporting to the ordering provider.

Coding Specifications

Modifier	Description	When to Use
`26`	Professional component	When billing only the professional component of the laboratory test if separated from the technical component.
`TC`	Technical component	When billing only the technical component (facility/instrumentation) of the test.
`91`	Repeat clinical diagnostic laboratory test	When the same test is repeated on the same day to obtain multiple results for clinical management.
`90`	Reference laboratory	When laboratory testing is performed by a reference (outside) laboratory and the billing reflects that circumstance.
`91`	Duplicate Result Clarification	When a repeat test is performed to confirm an unexpected result (note: `91` already listed; use once).
`59`	Distinct procedural service	When a separate and distinct diagnostic lab service is performed on the same day that is not typically bundled.
`QW`	CLIA waived test	When the specific assay is performed under CLIA-waived conditions (if applicable to the method).
`QK`	CLIA moderate complexity	When the test is performed under a CLIA-moderate complexity certification.
`QX`	Certified under CLIA by independent laboratory	When the performing technologist is CLIA-certified and billing requires identification.
`90`	Use by reference labs	When specimen is sent to an outside reference laboratory for analysis (note: `90` already listed; use once).

Taxonomy Code	Specialty	Notes
`207R00000X`	Anatomic/Clinical Pathology	Physicians who direct clinical laboratory testing and interpret results.
`207L00000X`	Clinical Laboratory	Laboratory directors and pathologists overseeing testing quality and reporting.
`163W00000X`	Diagnostic Radiology (supporting specialty)	Radiologists frequently coordinate with tumor marker testing during cancer workups.
`207K00000X`	Medical Oncology	Oncologists who use CA 125 values for diagnosis, staging, or monitoring therapy outcomes.

Related Diagnoses

ICD-10 Code	Description	Clinical Relevance
`C25.9`	Malignant neoplasm of pancreas, unspecified	Pancreatic cancer is a primary indication for tumor marker testing including CA 125 to assist in evaluation.
`C78.7`	Secondary malignant neoplasm of liver and intrahepatic bile duct	Metastatic disease assessment often accompanied by tumor marker measurement.
`R10.9`	Abdominal pain, unspecified	Symptom prompting workup including tumor markers when cancer is a differential diagnosis.
`R63.4`	Abnormal weight loss	Clinical sign that may trigger oncology evaluation with tumor marker testing.
`K86.1`	Alcohol-induced chronic pancreatitis	Chronic pancreatic disease that may prompt surveillance and differential diagnosis including malignancy.
`Z85.3`	Personal history of malignant neoplasm of breast	Prior malignancy history may motivate tumor marker surveillance when new symptoms emerge.
`Z08`	Encounter for follow-up examination after completed treatment for malignant neoplasm	Post-treatment monitoring where tumor markers can be used to detect recurrence.

Related CPT Codes

CPT Code	Description	Relationship to This Procedure
`36415`	Collection of venous blood by venipuncture	Specimen collection required prior to performing the `86304` assay.
`80053`	Comprehensive metabolic panel	Common accompanying laboratory panel ordered alongside tumor marker tests to assess organ function.
`85025`	Complete blood count (CBC) with automated differential	Frequently ordered in oncology evaluations to assess hematologic status during diagnosis and treatment.
`88305`	Level IV surgical pathology, gross and microscopic examination	Tissue pathology that provides definitive diagnosis complementary to tumor marker results.
`81002`	Urinalysis, non-automated, without microscopy	Ancillary test sometimes ordered in the evaluation of systemic disease and treatment monitoring.