CA19-9 Blood Test
The Cancer Antigen 19-9 is a protein that exists on the surface of certain cells. CA 19-9 does not cause cancer. Instead, it is a protein which is shed by tumor cells. Because of this it is useful as a tumor marker.
The CA19-9 blood test measures the amount of CA 19-9 in the blood stream. Low amounts of CA 19-9 can be detected in healthy people, and many conditions that affect the liver or pancreas can cause temporary elevations.
The test is used during radiation treatment and chemotherapy for colon or rectal cancer as a tumor marker to determine how well treatment is working. It is also used after treatment to determine after treatment whether cancer is gone and whether it has returned.
o There is nothing to do to prepare for the test.
o The test is performed like any normal blood test:
o An elastic band will be wrapped around your upper arm to stop the flow of blood and to make the veins below the band larger (which makes it easier to put in the needle.)
o Clean the site to be injected with alcohol to disinfect it.
o Put the needle into the vein.
o Attach a tube to the needle and fill it with blood.
o Remove the filled tube from your arm when enough blood is collected. A cotton pad or gauze pad is then put over the needle as it is removed.
o Pressure is put on the site which is then covered with a bandage.
o Results from the test are usually available within 1 – 3 days. (For tips to help cope with the waiting period, click here.)
o The results from the laboratory will show the normal range as well as yours. High values mean (that cancer is present, how cancer is responding to treatment and whether it has returned.)
CA 19-9 levels usually return to near-normal levels within 6 weeks of the end of treatment if cancer treatment is successful.
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