<unk>  testing <unk> T), as its name implies, aims to detect subtle<unk>  loss in the gastrointestinal tract, anywhere from the mouth to the colon. Positive tests ("positive stool") may result from either upper gastrointestinal bleeding or lower gastrointestinal bleeding and warrant further investigation for peptic ulcers or a malignancy (such as colorectal cancer or gastric cancer). The test does not directly detect colon cancer but is often used in clinical screening for that disease. It can also be used to look for active<unk><unk>  loss in anemia or when there are gastrointestinal symptoms. Colorectal cancer screening An estimated 1–5% of large tested populations have a positive<unk>  test. Of those, about 2–10% have cancer, while 20–30% have adenomas. Screening methods for colon cancer depend on detecting either precancerous changes such as certain kinds of polyps or on finding early and thus more treatable cancer. The extent to which screening procedures reduce the risk of gastrointestinal cancer or deaths depends on the rate of precancerous and cancerous disease in that population. gFOBT (guaiac<unk>  test) and flexible sigmoidoscopy screening have each shown benefit. Other colon cancer screening tools such as iFOBT (immunochemical<unk>  test) or colonoscopy are also included in guidelines. In 2009 the American College of Gastroenterology (ACG) suggested that colon cancer screening modalities that are also directly preventive by removing precursor lesions should be given precedence, and prefer a colonoscopy every ten years in average-risk individuals, beginning at age 50. The ACG suggests that cancer detection tests such as any type of<unk>  are an alternative that is less preferred, and if a colonoscopy is declined, the FIT (fecal immunochemical test, or iFOBT) should be offered instead. The 2017 US Multi-Society Task Force (MSTF)'s recommended first-tier tests are a colonoscopy every 10 years or annual FIT test. If FIT is utilized, proper steps must be taken to ensure appropriate use and follow-up of abnormal FIT results. FIT tests however are not that useful in picking up adenomas, even when advanced. The United States Preventive Services Task Force (USPSTF)'s 2016 recommendation, instead of emphasizing specific screening approaches, has instead chosen to highlight that there is convincing evidence that colorectal cancer screening substantially reduces deaths from the disease among adults aged 50 to 75 years and that not enough adults are using this effective preventive intervention. The ACG and MSTF also included CT colonography every five years, and fecal DNA testing as considerations. All three recommendation panels recommended replacing any older low-sensitivity, guaiac-based<unk>  testing (gFOBT) with either newer high-sensitivity guaiac-based<unk>  testing (hs gFOBT) or fecal immunochemical testing (FIT). MSTF looked at six studies that compared high-sensitivity gFOBT (Hemoccult SENSA) to FIT, and concluded that there was no clear difference in overall performance between these methods. The American College of Gastroenterology has recommended the abandoning of gFOBT testing as a colorectal cancer screening tool, in favor of the fecal immunochemical test. Though the FIT test is preferred, even the guaiac<unk>  testing of average risk populations may have been sufficient to reduce the mortality associated with colon cancer by about 25%. With this lower efficacy, it was not always cost-effective to screen a large population with gFOBT. A LabCorp<unk>  immunoassay testing kit. If colon cancer is suspected in an individual (such as in someone with an unexplained anemia),<unk>  tests may not be clinically helpful. If a doctor suspects colon cancer, more rigorous investigation is necessary, whether or not the test is positive. In 2006, the Australian Government introduced the National Bowel Cancer Program which has been updated several times since; targeted screening will be done of all Australians aged from 50 to 74 by 2020. Cancer Council Australia recommended that<unk> T should be done every two years. People over 50 not yet eligible for the national program can arrange with their doctor for an<unk> T. The Canadian Cancer Society recommends that men and women aged 50 and over have an<unk> T at least every two years. In colon cancer screening, using only one sample of feces collected by a doctor performing a digital rectal examination is discouraged. The use of the M2-PK Test is encouraged over gFOBT for routine screening, as it may pick up tumors whether or not they are bleeding. It is able to detect 80 percent of colorectal cancers and 44 percent for adenoma > 1 centimeter, while gFOBT picks up 13 to 50 percent of colorectal cancers. Other sources of bleeding Gastrointestinal bleeding has many potential sources, and positive results usually result in further testing for the bleeding site, usually looking for lower gastrointestinal bleeding before upper gastrointestinal bleeding causes unless there are other clues. Colonoscopy is usually preferred to computerized tomographic colonography. A positive test can result from upper gastrointestinal bleeding or lower gastrointestinal bleeding. The common causes are: * 2–10%: cancer (colorectal cancer, gastric cancer) * 20–30% adenoma or polyps * Diverticular disease * Hemorrhoids * Inflammatory bowel disease * Angiodysplasia of the colon * Sickle cell anemia In the event of a positive<unk>  test, the next step in the workup is a form of visualization of the gastrointestinal tract by one of several means: # Sigmoidoscopy, an examination of the rectum and lower colon with a lighted instrument to look for abnormalities, such as polyps. # Colonoscopy, a more thorough examination of the rectum and entire colon. # Virtual colonoscopy # Upper gastrointestinal endoscopy. It is sometimes performed with chromoendoscopy, a method that assists the endoscopist by enhancing the visual difference between cancerous and normal tissue, by either marking the abnormally increased DNA content (toluidine blue) or failing to stain the tumor, possibly due to decreased surface glycogen on tumor cells(Lugol). Infrared fluorescent endoscopy and ultrasonic endoscopy can interrogate vascular abnormalities such as esophageal varices. # Double-contrast barium enema: a series of x-rays of the colon and rectum. Testing secretions for<unk>  The use of an<unk> T for bleeding from the mouth, nose, esophagus, lungs, stomach and the initial portion of the small intestine, while the same as fecal testing, is discouraged, due to technical considerations including poorly characterized test performance characteristics such as sensitivity, specificity, and analytical interference. However, chemical confirmation that coloration is due to<unk>  rather than coffee, beets, medications, or food additives can be of significant clinical assistance.
Fecal occult blood
Stool test
Bristol stool scale
Fecal fat test
Complete blood count
Stool osmotic gap
Fecal pH test
Lipid profile