Cancer antigen 15-3 (CA 15-3)

What it measures

CA 15-3 is a mucin antigen produced by breast epithelium. It is used to monitor treatment response in metastatic breast cancer and is not suitable for screening or early diagnosis.

Specimen and preparation

• Specimen: Serum or lithium-heparin plasma
• Tube: Gold top

Reference range

Reference ranges differ between laboratories, methods and populations. Always use the range printed on your own lab report.

Causes of high values

• Metastatic breast cancer
• Other adenocarcinomas (ovary, lung, pancreas)
• Benign breast and liver disease
• Hepatitis and cirrhosis

Method

Chemiluminescent immunoassay

Good to know

Normal levels are common in early breast cancer; follow trends with the same method.

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