A hemoccult test or fecal occult blood test might be indicated if you notice a change in your stool color or blood in your stool. The test detects abnormal gastrointestinal bleeding and can aid in the early diagnosis of colon cancer. But the exact source of bleeding requires further testing procedures. Specific dietary, vitamin and medication restrictions apply in preparation for the hemoccult test. Failure to maintain restrictions can cause inaccurate results.
Significance
The fecal occult blood test evaluates the amount of blood in a stool specimen to detect or rule out early colon cancer. Abnormal amounts of blood in the stool can be the only early symptom of colon cancer. The test is useful in evaluating anemia and abnormal gastrointestinal bleeding, according to Lab Tests Online. A positive test result is not diagnostic for cancer and follow-up testing is needed to locate the source of bleeding.
Test Preparation
You might be advised to refrain from eating foods like red meat, broccoli, turnips and horseradish for several days before the test. These foods interact with the chemicals used in the test and cause a false positive reaction. Vitamin C, or ascorbic acid, hampers the chemical reaction of the test and contributes to a false negative. Instructions can include avoiding aspirin and iron preparations and dental procedures that can cause bleeding and produce false positives.
Types
There are two types of tests to detect occult or hidden quantities of abnormal blood in the stool: the hemoccult test, FBOT or fecal occult blood test; and the fecal immunochemical test, or FIT. The fecal immunochemical test has no dietary, dental or medication restrictions. The FIT identifies bleeding only from the lower gastrointestinal tract. Both tests can screen for blood in the stool but are not diagnostic.
Procedure
The test requires collection of three stool samples, usually over three days. From each sample a small amount of stool is taken and applied to a test-specific filter paper and delivered to the lab. In the lab, chemicals are added to the stool to cause a reaction and the result is read by the technician. Color changes in the chemical reaction and the sources of false reactions are best interpreted by experienced lab personnel.
Benefit
The early detection of abnormal bleeding in the gastrointestinal tract can be life saving considering the high incidence of colon cancer. The American College of Surgeons has indicated that the fecal occult blood test has a sensitivity of 40 percent to 60 percent in detecting hidden bleeding. Blood might not be contained in all stool, so obtaining three samples on three days expands the probability of finding intermittent bleeding.
Results
If your results are positive, it can indicate abnormal bleeding at any point in the gastrointestinal tract. This can include peptic ulcers, diverticulosis, polyps, inflammatory bowel diseases, hemorrhoids, benign or malignant lesions, or blood swallowed from a nosebleed or bleeding gums. Follow-up screening might include a colonoscopy, according to the American College of Gastroenterology. Negative results might indicate noncompliance with restrictions, intermittent bleeding or that no active bleeding is occurring in your GI tract.
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