A fecal occult blood test (FOBT) checks for hidden blood in your stool. The doctor may place a small amount of your stool on a plastic slide or a special type of paper, or you may do this test at home. Stomach cancer can sometimes cause small amounts of bleeding that is hard to see. But so can certain noncancerous conditions. Even if the test shows blood in your stool, you may need other tests to confirm whether or not it is due to cancer.
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