Cancer Antigen (CA) 15-3

Alternate Name: Ca15-3

SAL Code:






Turn Around Time:

1 Day






Tumor Markers

Performing Laboratory:

Sherman Abrams Laboratory

Specimen Requirements:

Primary Tube:


Primary Substance:




Stable Ambient:

7 Days

Stable Fridge:

7 Days

Stable Frozen:

28 Days

Clinical Info:

In general, the higher the CA 15-3 level, the more advanced the breast cancer and the larger the tumor burden. CA 15-3 concentrations tend to increase as the cancer grows. In metastatic breast cancer, the highest levels of CA 15-3 often are seen when the cancer has spread to the bones and/or the liver. Increasing concentrations of CA 15-3 over time may indicate that a person is not responding to treatment or that the cancer is recurring. Levels within the normal range do not preclude the presence of cancer, nor are elevated results an absolute indication of malignancy. CA 125 test results should be interpreted in conjunction with other clinical and laboratory findings.

Additional Information:

CA 15-3 may be ordered along with other tests, such as estrogen and progesterone receptors, Her2/neu, and gene expression tests for breast cancer, when advanced breast cancer is first diagnosed to help determine cancer characteristics and treatment options. If CA 15-3
is initially elevated, then it may be ordered periodically to monitor the effectiveness of treatment and to help watch for recurrence. CA 15-3 is usually not ordered
when breast cancer is detected early, before it has metastasized, because levels will not be elevated in the majority of early cancers.

Sample Collection:

Collect patient samples using standard phlebotomy techniques. Click here for additional collection instructions.

Test Limitations:

Benign diseases of the breast and liver may cause elevated results. Falsely elevated or depressed values may occur in samples obtained from patients who have received mouse monoclonal antibody preparations during diagnosis or therapy. Such patients may have
developed human anti-mouse antibodies (HAMA) that interfere with accurate analysis.
Values obtained with different assay methods should not be used interchangeably in serial testing. It is recommended that only one assay method be used consistently to monitor each patient's course of therapy.

Specimen Handling Instructions:

Centrifuge immediately after clot formation to separate serum/plasma from cells.

Test Information: