What is this test?
This test measures the presence and amount of cancer antigen 15-3. This test is uses a tumor marker to help monitor patients with breast cancer. A sample of blood, pleural fluid, peritoneal fluid, pericardial (around the heart) fluid, or other body fluid may be collected for this test.
What are related tests?
Why do I need this test?
Laboratory tests may be done for many reasons. Tests are performed for routine health screenings or if a disease or toxicity is suspected. Lab tests may be used to determine if a medical condition is improving or worsening. Lab tests may also be used to measure the success or failure of a medication or treatment plan. Lab tests may be ordered for professional or legal reasons. You may need this test if you have:
When and how often should I have this test?
When and how often laboratory tests are done may depend on many factors. The timing of laboratory tests may rely on the results or completion of other tests, procedures, or treatments. Lab tests may be performed immediately in an emergency, or tests may be delayed as a condition is treated or monitored. A test may be suggested or become necessary when certain signs or symptoms appear.
Due to changes in the way your body naturally functions through the course of a day, lab tests may need to be performed at a certain time of day. If you have prepared for a test by changing your food or fluid intake, lab tests may be timed in accordance with those changes. Timing of tests may be based on increased and decreased levels of medications, drugs or other substances in the body.
The age or gender of the person being tested may affect when and how often a lab test is required. Chronic or progressive conditions may need ongoing monitoring through the use of lab tests. Conditions that worsen and improve may also need frequent monitoring. Certain tests may be repeated to obtain a series of results, or tests may need to be repeated to confirm or disprove results. Timing and frequency of lab tests may vary if they are performed for professional or legal reasons.
How should I get ready for the test?
Before having blood collected, tell the person drawing your blood if you are allergic to latex. Tell the healthcare worker if you have a medical condition or are using a medication or supplement that causes excessive bleeding. Also tell the healthcare worker if you have felt nauseated, lightheaded, or have fainted while having blood drawn in the past.
A thoracentesis is a procedure that requires written consent. Review the consent form with the healthcare worker and ask any questions that you have before signing the consent form. Tell the healthcare worker if you have a medical condition or are using a medication or supplement that causes excessive bleeding. You should also report if you have a history of allergic or other reactions to local anesthetics. You may need to have blood tests and a chest x-ray performed before the thoracentesis.
A paracentesis is a procedure that requires written consent. Review the consent form with the healthcare worker and ask any questions that you have before signing the consent form.
Tell the healthcare worker if you have a medical condition or are using a medication or supplement that causes excessive bleeding. You should also report if you have a history of allergic or other reactions to local anesthetics. You may be asked to empty your bladder before the procedure. Your vital signs, weight, and waist measurement will be recorded before and after a paracentesis.
Other body fluid:
A different sample other than the samples listed above may be used for this test. Ask your healthcare worker for information about how to prepare for this test. If you have questions or concerns about the preparation for this test, talk to the healthcare worker.
How is the test done?
A sample of blood, pleural fluid, peritoneal fluid, pericardial fluid, or other body fluid may be collected for this test.
When a blood sample from a vein is needed, a vein in your arm is usually selected. A tourniquet (large rubber strap) may be secured above the vein. The skin over the vein will be cleaned, and a needle will be inserted. You will be asked to hold very still while your blood is collected. Blood will be collected into one or more tubes, and the tourniquet will be removed. When enough blood has been collected, the healthcare worker will take the needle out.
Pleural fluid is the fluid in between the membrane linings of your lungs. A procedure called a thoracentesis is done to get a pleural fluid sample for testing. A healthcare worker will first need to locate the fluid that needs to be sampled. This is done by a chest x-ray, ultrasound, or by percussion (rhythmically pounding the chest wall). Once the fluid is located, a healthcare worker may hold up the arm on the same side where the procedure will be done. Your skin will be cleaned with antiseptic, and a local anesthetic is injected to numb the area. A needle will be inserted into the fluid pocket. Fluid samples are then drawn out using a needle attached to a syringe. When a large enough sample is collected, the needle will be removed. A thoracentesis may be done with or without the assistance of ultrasound or CT scan.
Peritoneal fluid is the fluid in the space between the membrane linings of the abdomen wall and organs in the abdominal cavity. A paracentesis is a procedure that may be used to obtain a sample of peritoneal fluid. For this procedure, your skin will be shaved and cleaned, and a sterile area will be prepared. A local anesthetic will be used to numb the procedure area. A needle will be inserted through the abdominal wall into a fluid pocket. Sometimes a small incision is made to help insert the needle.
If fluid removal is difficult, you may need to change positions during the procedure to drain different pockets of fluid. After enough fluid has drained, the needle will be removed.
Other body fluid:
A different sample other than the samples listed above may be used for this test. Methods used to collect other body fluids or tissue samples may vary. Ask the healthcare worker to explain how this sample may be collected. If you have questions or concerns about this test, talk to the healthcare worker.
How will the test feel?
The amount of discomfort you feel will depend on many factors, including your sensitivity to pain. Communicate how you are feeling with the person doing the test. Inform the person doing the test if you feel that you cannot continue with the test.
During a blood draw, you may feel mild discomfort at the location where the blood sample is being collected.
Before a thoracentesis, a local anesthetic is given to the procedure site to numb the area. You may feel mild discomfort or stinging when the numbing medicine is injected. You may still be able to feel pressure or discomfort during the procedure. Your procedure site may be sore for several days.
For a paracentesis, a local anesthetic is given to numb the procedure area and decrease pain. When the numbing medicine is injected, you may feel mild discomfort or stinging. Brief pain may be felt as the needle passes through the abdominal wall. If you have a large build-up of extra peritoneal fluid, this procedure may decrease or relieve abdominal discomfort or difficulty breathing. If a large quantity of fluid is removed you may feel dizzy or light-headed. Tell the person doing the test if you feel dizzy or light-headed. The procedure site may be sore for several days.
Other body fluid:
A different sample other than the samples listed above may be used for this test. This test may feel different depending on many factors, including the sample needed and how it is collected. Ask the healthcare worker what to expect during this test.
What should I do after the test?
After a blood sample is collected from your vein, a bandage, cotton ball, or gauze may be placed on the area where the needle was inserted. You may be asked to apply pressure to the area. Avoid strenuous exercise immediately after your blood draw. Contact your healthcare worker if you feel pain or see redness, swelling, or discharge from the puncture site.
After a thoracentesis, a bandage will be secured over your procedure site and pressure held until the bleeding or fluid leakage stops. You may receive a chest x-ray to check for complications. The chest x-ray may be repeated to look for the return of fluid in the lung. Follow your healthcare worker’s instructions for changing your bandage and other wound care. Tell your healthcare worker immediately if you have a new onset of difficulty breathing, shortness of breath, chest pain, weakness, fatigue, fever, or dizziness. Also immediately tell your healthcare worker if you have increased bleeding or drainage from the procedure site.
After paracentesis is used to collect a sample of peritoneal fluid, pressure may be applied and a bandage will be secured over the puncture site. Your puncture site bandage and vital signs will be monitored frequently for a period of time after this procedure. Tell your healthcare worker immediately should you feel dizziness or weakness shortly after the procedure.
You will be given instructions for how to care for your bandage, and signs and symptoms of infection to watch for. Contact your healthcare worker if you develop a fever or increased pain, and if you see continued drainage, increasing redness, swelling, or pus formation at the procedure site.
After a paracentesis, healthcare workers may need to check your urine for any blood, as this may be a sign of bladder injury. Watch for any blood in your urine for at least 24 hours after the procedure. If you see blood in your urine, contact your healthcare worker immediately.
Other body fluid:
A different sample other than the samples listed above may be used for this test. Instructions for what to do after a collection of other body fluid or tissue samples may vary. Ask the healthcare worker to instruct you on what to expect after this test is completed. If you have questions or concerns about what to expect after the test is completed, talk to the healthcare worker.
What are the risks?
Blood: During a blood draw, a hematoma (blood-filled bump under the skin) or slight bleeding from the puncture site may occur. After a blood draw, a bruise or infection may occur at the puncture site. The person doing this test may need to perform it more than once. Talk to your healthcare worker if you have any concerns about the risks of this test.
Pleural fluid: A procedure called a thoracentesis is done to collect a pleural fluid sample for testing. Common risks of a thoracentesis include bleeding and bruising at the puncture site and pneumothorax (collapsed lung). If you have a medical condition, or are using a medication or supplement that causes excessive bleeding, you are at a higher risk of bleeding from the puncture site. Rare risks include hemothorax (blood in the chest cavity), pulmonary edema (accumulation of fluid in the lungs), and venous air embolism (air bubble in a vein). Your liver or spleen may be damaged by the needle used during the procedure. The person doing this procedure may need to perform it more than once. Talk to your healthcare worker if you have any concerns about the risks of having a thoracentesis.
Peritoneal fluid: A procedure called a paracentesis is done to collect a sample of peritoneal fluid for testing. Risks of a paracentesis include infection and severe bleeding. The needle used to do the procedure may damage an organ in the abdomen. If a large quantity of fluid is removed, your blood pressure may drop too low. If you have a medical condition, or are using a medication or supplement that causes excessive bleeding, you are at a higher risk of bleeding from the puncture site. The person doing this procedure may need to perform it more than once. Talk to your healthcare worker if you have any concerns about the risks of having a paracentesis.
Other body fluid or tissue samples: A different sample other than the samples listed above may be used for this test. Ask your healthcare worker to explain the risks of this test to you. If you have questions or concerns about this test, talk to the healthcare worker.
What are normal results for this test?
Laboratory test results may vary depending on your age, gender, health history, the method used for the test, and many other factors. If your results are different from the results suggested below, this may not mean that you have a disease. Contact your healthcare worker if you have any questions. The following is considered to be a normal result for this test:
- Adults (serum): 0-30 units/mL (0-30 kilounits/L) 
What follow up should I do after this test?
Ask your healthcare worker how you will be informed of the test results. You may be asked to call for results, schedule an appointment to discuss results, or notified of results by mail. Follow up care varies depending on many factors related to your test. Sometimes there is no follow up after you have been notified of test results. At other times follow up may be suggested or necessary. Some examples of follow up care include changes to medication or treatment plans, referral to a specialist, more or less frequent monitoring, and additional tests or procedures. Talk with your healthcare worker about any concerns or questions you have regarding follow up care or instructions.
Where can I get more information?
- American Cancer Society - http://www.cancer.org
- National Cancer Institute - http://www.cancer.gov
 Henry JB: Clinical Diagnosis and Management by Laboratory Methods, 20th ed. Saunders, 2001.
 Zimmerman RL MD, Fogt F MD, & Goonewardene S MD: Diagnostic value of a second generation CA 15-3 antibody to detect adenocarcinoma in body cavity effusions. Cancer 2000; 90:230-234.
 Tietz NW (Ed): Clinical Guide to Laboratory Tests, 3rd ed. W. B. Saunders, Philadelphia, PA, 1995.
 Duffy MJ, Duggan C, Keane R, et al: High preoperative CA 15-3 concentrations predict adverse outcome in node-negative and node-positive breast cancer: study of 600 patients with histologically confirmed breast cancer. Clin Chem 2004; 50(3):559-563.
 Bast RC Jr, Ravdin P, Hayes DF, et al: 2000 Update of recommendations for the use of tumor markers in breast and colorectal cancer: clinical practice guidelines of the American Society of Clinical Oncology.. J Clin Oncol. 2001; 19:1865-78.
 Bast RC Jr, Ravdin P, Hayes DF, et al: Erratum to 2000 update of recommendations for the use of tumor markers in breast and colorectal cancer: clinical practice guidelines of the American Society of Clinical Oncology. J Clin Oncol 2001; 19(21):4185-4188.
 Shering SG, Sherry F, McDermott EW, et al: Preoperative CA 15-3 concentrations predict outcome of patients with breast carcinoma. Cancer 1998; 83(12)::2521-2527.
 Kratz A, Ferraro M, Sluss PM, et al: Case records of the Massachusetts General Hospital: laboratory values. N Engl J Med 2004; 351(15):1549-1563.
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