CA 15-3 is a protein produced by breast cells. This test measures CA 15-3 levels in the blood and is primarily used to monitor treatment response in patients with advanced breast cancer.
Category: Tumor Markers
Also known as: ca 15-3, ca15-3, ca 15 3, cancer antigen 15-3
Reference range: 0–30 U/mL (Source: ABIM)
Standard unit: U/mL
High values may indicate
High CA 15-3 levels may indicate breast cancer (especially metastatic), ovarian cancer, lung cancer, or non-cancerous conditions such as liver disease, lupus, or benign breast disease.
Low values may indicate
Low CA 15-3 levels are normal and may indicate a good response to breast cancer treatment in patients being monitored.