Doctor's Assessment Included
Every result includes a professional assessment from a BIG-registered doctor. For treatment decisions, discuss your results with your GP.
CA 15-3
CA 15-3 is a glycoprotein produced by breast cells. As a woman, understanding this marker is an important part of proactive breast health awareness. Elevated levels can result from many benign conditions — including non-cancerous breast changes and endometriosis — and should always be interpreted by a qualified healthcare provider.
What It Measures
CA 15-3 measures the blood concentration of a glycoprotein shed by breast epithelial cells. Higher concentrations may reflect increased cellular turnover or secretion from breast tissue, but the result alone cannot confirm or exclude any specific diagnosis.
Why It Matters
Tracking CA 15-3 over time can give clinicians useful information about how breast tissue is behaving. Rising trends may prompt further investigation, while a stable or falling result can be reassuring in a monitoring context. A single elevated result should always be interpreted alongside other clinical information by a qualified healthcare provider.
When to Test
CA 15-3 testing is typically ordered by a healthcare provider as part of ongoing monitoring rather than routine screening. Consult your healthcare provider before arranging this test independently.
Symptoms
Low Levels
Low CA 15-3 levels are generally not associated with specific symptoms and are considered within the normal reference range.
High Levels
An elevated CA 15-3 result on its own does not cause symptoms. It is a laboratory finding that may prompt further evaluation. Many people with elevated CA 15-3 have entirely benign underlying causes such as liver disease, benign breast conditions, or endometriosis.
Lifestyle Tips
Maintaining a healthy lifestyle — including a balanced diet, regular physical activity, a healthy body weight, limiting alcohol, and not smoking — supports overall breast and general health. These habits do not directly lower CA 15-3 but contribute to your broader health. Always discuss significant lifestyle changes with your healthcare provider.
Frequently Asked Questions
Does an elevated CA 15-3 mean I have cancer?
No. Many benign conditions — including non-cancerous breast disease, liver conditions, and endometriosis — can raise CA 15-3. Only a qualified healthcare provider can interpret what an elevated result means for your specific situation.
Can CA 15-3 be used as a routine screening test?
CA 15-3 is not recommended as a routine cancer screening tool because it lacks the specificity and sensitivity required for that purpose. It is most useful when used by clinicians to monitor a known condition over time.
Do I need to prepare specially before a CA 15-3 blood test?
No special preparation is generally required. Follow any instructions provided by your testing service or healthcare provider.