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Interpretive Handbook

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Test 81607 :
Cancer Antigen 15-3 (CA 15-3), Serum

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Carcinoma of the breast is the most prevalent form of cancer in women. These tumors often produce mucinous antigens that are large molecular weight glycoproteins with O-linked oligosaccharide chains. Tumor-associated antigens encoded by the human MUC-1 gene are known by several names, including MAM6, milk mucin antigen, cancer antigen (CA) 27.29, and CA 15-3.

 

CA 15-3 assay values are not elevated in most normal individuals and are frequently elevated in sera from breast cancer patients.

 

Nonmammary malignancies in which elevated CA 15-3 assay values have been reported include: lung, colon, pancreas, primary liver, ovary, cervix, and endometrium.

Useful For Suggests clinical disorders or settings where the test may be helpful

The management of breast cancer patients when used in conjunction with clinical information and other diagnostic procedures. Serial testing can assist in early detection of disease recurrence in previously treated stage II and III breast cancer patients

 

Monitoring response to therapy in metastatic breast cancer patients

Interpretation Provides information to assist in interpretation of the test results

Increasing and decreasing values show correlation with disease progression and regression, respectively.(1) Increasing cancer antigen 15-3 (CA 15-3) assay values in patients at risk for breast cancer recurrence after primary therapy may be indicative of recurrent disease before it can be detected clinically (2,3) and may be used as an indication that additional tests or procedures should be performed.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Testing for cancer antigen 15-3 (CA 15-3) should be performed in conjunction with other clinical methods used for the early detection of recurrence.

 

Measurement of CA 15-3 is not useful as a cancer-screening test.

 

Some patients, who have been exposed to mouse antigens, whether in the environment or as part of treatment or imaging procedures, may have circulating antimouse antibodies. These antibodies may interfere with the assay reagents to produce unreliable CA 15-3 assay results

 

Wait at least 8 hours after the last biotin administration before drawing a specimen from patients receiving therapy with high doses of biotin (ie, >5 mg/day) to avoid assay interference.

 

In rare cases, interference due to extremely high titers of antibodies to ruthenium or streptavidin can occur.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Males: <30 U/mL (use not defined)

Females: <30 U/mL

Clinical References Provides recommendations for further in-depth reading of a clinical nature

1. Molina R, Zanon G, Filella X, et al: Use of serial carcinoembryonic antigen and CA 15-3 assays in detecting relapses in breast cancer patients. Breast Cancer Res Treat 1995;36:41-48

2. Geraghty JG, Coveney EC, Sherry F, et al: CA 15-3 in patients with locoregional and metastatic breast carcinoma. Cancer 1992;70:2831-2834

3. Kallioniemi OP, Oksa H, Aaran RK, et al: Serum CA 15-3 assay in the diagnosis and follow-up of breast cancer. Br J Cancer 1988;58:213-215


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