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Test Code 280 Cancer Antigen 125 (CA 125)

Important Note

Important Note

Human anti-mouse antibodies (hama) may be present in samples from patients who have received immunotherapy or diagnostic procedures utilizing monoclonal antibodies or in individuals who have been regularly exposed to animals. Additionally, other heterophile antibodies, such as human anti-goat antibodies may be present in patient samples. Manufacturers formulate assays to minimize the effects of these antibodies; however careful evaluation of patient results must be done when patients are known to have such antibodies.

Additional Codes


PowerChart: CA 125

MA Cerner: CA-125

Specimen Requirement

0.5 mL serum or plasma is required.

Additional Specimen Collection Information

Collect blood in a lithium heparin, green-top or red-top tube. PST and SST (gel tubes) are acceptable. Serum or plasma should be separated from contact with the cells within 2 hours of collection. Specimens not centrifuged within 4 hours of collection may be rejected. Refrigerate the specimen if unable to assay within 8 hours of collection. Samples with ≥2+ lipemia must be cleared prior to analysis.

Useful For

Evaluating patients' response to cancer therapy, especially for ovarian carcinoma.

Predicting recurrent ovarian cancer or intraperitoneal tumor.


Testing is performed Monday through Sunday.

Typically completed within 4 hours after the specimen arrives at the testing site.

CPT Code Information

 86304 Diagnostic Immunology Testing: Immunoassay for tumor antigen, quantitative; CA 125

LOINC Code Information

10334-1 Cancer Ag 125 [Units/Volume] In Serum Or Plasma

Test Method

Paramagnetic Particle, Chemiluminescent Immunoassay; Beckman Access OV Monitor

Reference Values

< 35 U/mL