Fecal occult blood is a screening that looks for tiny traces of blood in stool (poop). It helps healthcare providers diagnose several conditions. Examples include anemia, when the body doesn't have enough healthy red blood cells; colitis, inflammation or irritation in your colon; diverticulosis, which are expanded pockets on your colon wall; and hemorrhoids, swollen veins inside your rectum or outside of your anus. You may also have occult blood in your stool because of serious dental disease, internal parasites, tumors, or from swallowing a foreign object like a small toy.
Occult blood in the intestines can also be a sign of colorectal cancer, which is why experts recommend regular stool tests for people age 45 and older. Screening can help identify the cancer early and improve your chance of survival.
There are two kinds of fecal occult blood tests: the guaiac fecal occult blood test (gFOBT) and the immunochemical fecal occult blood testing kit (iFOBT or FIT-DNA). You can buy iFOBT kits without a prescription in some pharmacies, but you'll need to send the kit to a lab for testing. gFOBTs are available at most pharmacies and some supermarkets, but you need to be careful about how you store and handle them. They should be kept at room temperature and away from light and heat.
When you get the gFOBT kit, follow the instructions to collect samples from at least three bowel movements in clean containers over the course of four days. Then, use an applicator stick to put a small smear of the stool on a test card. Place the test cards in a sealed envelope and mail them to a laboratory for testing.
You can also get a Hemoccult kit without a doctor's order. These kits come with plastic collection tubes and an applicator stick. Follow the instructions on the kit to collect and store the sample. Don't put the Hemoccult slide or applicator stick in your toilet tank. It's best to keep them on a counter or somewhere dry where they won't get wet.
The results from a Hemoccult test 血便 should be ready in about a week. If the results are positive, your healthcare provider will talk with you about next steps. They may recommend more tests to figure out the location and cause of the bleeding. The most common follow-up test is a colonoscopy.
Expert medical groups strongly recommend that most adults age 45 and older get regular fecal occult blood screenings to detect colorectal cancer. If you have a family history of the disease or other risk factors, your health care provider may suggest that you start screening earlier. The test is not 100% accurate, and it may miss some premalignant or early-stage colon cancers. However, it is much better than no screening at all. Regular fecal occult blood screens, combined with regular colorectal cancer exams, can significantly reduce the number of deaths from the disease.
