Serum CA 15-3

Specimen Required

3-5cc Clotted Blood or Serum

Fasting Required

Purpose of the Serum CA 15-3 Test

To monitor the response to treatment of breast cancer and to watch for recurrence of the disease

When this Serum CA 15-3 test is required

CA 15-3 may be requested during follow-up following surgical removal of a breast cancer. It may be also requested when a patient with advanced breast cancer is receiving treatment. Changes in the concentration of CA 15-3 may indicate if a tumour is responding to treatment.

What the Serum CA 15-3 Test Detects

Cancer antigen 15-3 (CA 15-3) is a normal product of breast cells. Concentrations of CA 15-3 in the blood are often increased in breast cancer. CA 15-3 does not cause cancer; rather, it is a protein that is shed by the tumour cells, making it useful as a marker to follow the course of the cancer.CA 15-3 is rarely elevated in women with localised breast cancer but is increased in about 75% of those with breast cancer that has metastasised (spread to other organs). CA 15-3 also may be elevated in healthy people and in individuals with other cancers, or diseases, such as bowel cancer, lung cancer, cirrhosis, hepatitis, and benign breast disease.How is the sample collected for testing?A blood sample is obtained by inserting a needle into a vein in the arm.Is any test preparation needed to ensure the quality of the sample?No test preparation is needed.See MoreSee Less

Preparation for the Serum CA 15-3 Test

None

Sample Requirements

A blood sample taken from a vein in your arm

Additional Notes

A test to determine the concentration of CA 15-3 in your blood will not usually be performed immediately after breast cancer treatment begins because there have been instances of temporary increases and decreases in CA 15-3 that do not match with the patient’s progress. Usually, your doctor will wait a few weeks after starting treatment to begin monitoring CA 15-3 concentrations.

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