Cancer Antigen 15-3
(CA 15-3)

Sample type:

Serum.

Uses:

• This test measures the amount of cancer antigen 15-3 (CA 15-3) in your blood. CA 15-3 is a substance that stimulates your body’s defense system. Some kinds of cancer cells release the CA 15-3 antigen into the blood. This test is used to monitor certain types of cancer as breast cancer.

Precautions:

• Certain medications and supplements can interfere with the CA 15-3 test. Among them is biotin (also known as vitamin B7, vitamin B8, vitamin H, or coenzyme R). The CA 15-3 test relies on biotin to bind to the CA 15-3 antigen and may be affected if too much biotin is consumed.

• While the recommended daily intake of biotin is unlikely to cause any harm, high-dose biotin supplements may trigger false-negative readings. Stop taking any supplement containing more than 0.03 milligrams of biotin 72 hours before the test.

Interfering Factors:

• Test results may vary depending on your age, gender, health history, the method used for the test, and other things. Your test results may not mean you have a problem.

Pre analytical errors:

1) Taking supplement containing more than 0.03 milligrams of biotin 72 hours before the test.

2) Giving the patient not sufficient amount of the targeted cancer drug Afinitor (everolimus).

Corrective action:

1) Stop taking biotin 72hrs before the test.

2) Giving the patient sufficient amount of everolimus.

Post analytical errors:

1) Failure in reporting.

2) Erroneous validation of analytical data.

3) Improper data entry.

Corrective action:

1) Write correct report.

2) All analytical data should be valid

3) Proper data entery.

Reference range:

The reference range of serum CA 15-3 is less than 30 U/mL. The upper limit of the range varies depending on the laboratory and kit used for the test.