| Stool test | |
|---|---|
 Transport vials filled with human feces for stool testing. Yellow and blue tops for parasite testing, red top for stool cultures and the white top was provided by the patient with the sample. | |
| Purpose | diagnose if medical condition is present |
A stool test is a medical diagnostic technique that involves the collection and analysis of fecal matter. Microbial analysis (culturing), microscopy and chemical tests are among the tests performed on stool samples.
Stool samples should be sent to the laboratory as soon as possible after collection and should not be refrigerated prior to by the laboratory. [1]
The patient and/or health care worker in the office or at the bedside is able to make some important observations.
Fecal occult blood test and fecal immunochemical test are the most common stool tests to diagnose many conditions that caused by bleeding in the gastrointestinal system, including colorectal cancer or stomach cancer. [2] 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 (FIT). [3] The newer and recommended tests look for globin, DNA, or other blood factors including transferrin, while conventional stool guaiac tests look for heme.
Cancers, and to a lesser extent, precancerous lesions, shed abnormal cells into the stool. [4] Cancers and precancerous lesions (polyps) that are ulcerated or rubbed by passing stool also may shed blood into the stool, which can be identified by a hemoglobin assay. [4]
The American Cancer Society and the U.S. Preventive Services Task Force recommended colorectal cancer screening with a fecal immunochemical test every year, or a multi-target stool DNA test for every three years from the age of 45. [5] Other options include a sigmoidoscopy or virtual colonoscopy (CT colonography) for every five years or a colonoscopy for every 10 years. Fecal occult blood test is no longer recommended due to the high false-positive rate as well as the dietary and pharmaceutical restrictions. [5] [6] The National Committee for Quality Assurance (NCQA) issued an update to the Healthcare Effectiveness Data and Information Set (HEDIS) for 2017, while the guideline remains for the patients aged 50 or over. [7]
A multi-target stool DNA test was approved in August 2014 by the FDA as a screening test for non-symptomatic, average-risk adults 50 years or older. [8] A 2017 study found this testing to be less cost effective compared to colonoscopy or fecal occult blood testing. [9] Three-year multi-target stool DNA test has been estimated to cost $11,313 per quality-adjusted life year (QALY) compared with no screening. [10]
Parasitic diseases such as ascariasis, hookworm, strongyloidiasis and whipworm can be diagnosed by examining stools under a microscope for the presence of worm larvae or eggs. Some bacterial diseases can be detected with a stool culture. Toxins from bacteria such as Clostridium difficile ("C. diff.") can also be identified. Viruses such as rotavirus can also be found in stools. [11]
A fecal pH test may be used to determine lactose intolerance or the presence of an infection. [12] Steatorrhea can be diagnosed using a fecal fat test, which checks for the malabsorption of fat. [13]
Faecal elastase levels are becoming the mainstay of pancreatitis diagnosis.
The large intestine, also known as the large bowel, is the last part of the gastrointestinal tract and of the digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces before being removed by defecation. The colon is the longest portion of the large intestine, and the terms are often used interchangeably but most sources define the large intestine as the combination of the cecum, colon, rectum, and anal canal. Some other sources exclude the anal canal.
Colorectal cancer (CRC), also known as bowel cancer, colon cancer, or rectal cancer, is the development of cancer from the colon or rectum. Signs and symptoms may include blood in the stool, a change in bowel movements, weight loss, abdominal pain and fatigue. Most colorectal cancers are due to old age and lifestyle factors, with only a small number of cases due to underlying genetic disorders. Risk factors include diet, obesity, smoking, and lack of physical activity. Dietary factors that increase the risk include red meat, processed meat, and alcohol. Another risk factor is inflammatory bowel disease, which includes Crohn's disease and ulcerative colitis. Some of the inherited genetic disorders that can cause colorectal cancer include familial adenomatous polyposis and hereditary non-polyposis colon cancer; however, these represent less than 5% of cases. It typically starts as a benign tumor, often in the form of a polyp, which over time becomes cancerous.
Colonoscopy or coloscopy is a medical procedure involving the endoscopic examination of the large bowel (colon) and the distal portion of the small bowel. This examination is performed using either a CCD camera or a fiber optic camera, which is mounted on a flexible tube and passed through the anus.
In anatomy, a polyp is an abnormal growth of tissue projecting from a mucous membrane. If it is attached to the surface by a narrow elongated stalk, it is said to be pedunculated; if it is attached without a stalk, it is said to be sessile. Polyps are commonly found in the colon, stomach, nose, ear, sinus(es), urinary bladder, and uterus. They may also occur elsewhere in the body where there are mucous membranes, including the cervix, vocal folds, and small intestine. Some polyps are tumors (neoplasms) and others are non-neoplastic, for example hyperplastic or dysplastic, which are benign. The neoplastic ones are usually benign, although some can be pre-malignant, or concurrent with a malignancy.
Digital rectal examination (DRE), also known as a prostate exam, is an internal examination of the rectum performed by a healthcare provider.
Fecal occult blood (FOB) refers to blood in the feces that is not visibly apparent. A fecal occult blood test (FOBT) checks for hidden (occult) blood in the stool (feces).
In medicine (gastroenterology), angiodysplasia is a small vascular malformation of the gut. It is a common cause of otherwise unexplained gastrointestinal bleeding and anemia. Lesions are often multiple, and frequently involve the cecum or ascending colon, although they can occur at other places. Treatment may be with colonoscopic interventions, angiography and embolization, medication, or occasionally surgery.
Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and a variety of anaemias.
Gastrointestinal bleeding, also called gastrointestinal hemorrhage (GIB), is all forms of bleeding in the gastrointestinal tract, from the mouth to the rectum. When there is significant blood loss over a short time, symptoms may include vomiting red blood, vomiting black blood, bloody stool, or black stool. Small amounts of bleeding over a long time may cause iron-deficiency anemia resulting in feeling tired or heart-related chest pain. Other symptoms may include abdominal pain, shortness of breath, pale skin, or passing out. Sometimes in those with small amounts of bleeding no symptoms may be present.
Virtual colonoscopy is the use of CT scanning or magnetic resonance imaging (MRI) to produce two- and three-dimensional images of the colon, from the lowest part, the rectum, to the lower end of the small intestine, and to display the images on an electronic display device. The procedure is used to screen for colon cancer and polyps, and may detect diverticulosis. A virtual colonoscopy can provide 3D reconstructed endoluminal views of the bowel. VC provides a secondary benefit of revealing diseases or abnormalities outside the colon.
Blood in stool or rectal bleeding looks different depending on how early it enters the digestive tract—and thus how much digestive action it has been exposed to—and how much there is. The term can refer either to melena, with a black appearance, typically originating from upper gastrointestinal bleeding; or to hematochezia, with a red color, typically originating from lower gastrointestinal bleeding. Evaluation of the blood found in stool depends on its characteristics, in terms of color, quantity and other features, which can point to its source, however, more serious conditions can present with a mixed picture, or with the form of bleeding that is found in another section of the tract. The term "blood in stool" is usually only used to describe visible blood, and not fecal occult blood, which is found only after physical examination and chemical laboratory testing.
Rectal bleeding refers to bleeding in the rectum. There are many causes of rectal hemorrhage, including inflamed hemorrhoids, rectal varices, proctitis, stercoral ulcers and infections. Diagnosis is usually made by proctoscopy, which is an endoscopic test.
Lower gastrointestinal bleeding, commonly abbreviated LGIB, is any form of gastrointestinal bleeding in the lower gastrointestinal tract. LGIB is a common reason for seeking medical attention at a hospital's emergency department. LGIB accounts for 30–40% of all gastrointestinal bleeding and is less common than upper gastrointestinal bleeding (UGIB). It is estimated that UGIB accounts for 100–200 per 100,000 cases versus 20–27 per 100,000 cases for LGIB. Approximately 85% of lower gastrointestinal bleeding involves the colon, 10% are from bleeds that are actually upper gastrointestinal bleeds, and 3–5% involve the small intestine.
The stool guaiac test or guaiac fecal occult blood test (gFOBT) is one of several methods that detects the presence of fecal occult blood. The test involves placing a fecal sample on guaiac paper and applying hydrogen peroxide which, in the presence of blood, yields a blue reaction product within seconds.
A colorectal polyp is a polyp occurring on the lining of the colon or rectum. Untreated colorectal polyps can develop into colorectal cancer.
The objective of cancer screening is to detect cancer before symptoms appear, involving various methods such as blood tests, urine tests, DNA tests, and medical imaging. The purpose of screening is early cancer detection, to make the cancer easier to treat and extending life expectancy. In 2019, cancer was the second leading cause of death globally; more recent data is pending due to the COVID-19 pandemic.
The M2-PK Test is a non-invasive screening method for the early detection of colorectal cancers and polyps which are known to be the precursors of colorectal cancer. The M2-PK Test which is used for stool analysis is available either as fully quantitative ELISA Test or as a rapid test that can be performed by any general practitioner without the need of a laboratory or any additional equipment.
A rectovaginal examination is a type of gynecological examination used to supplement a pelvic examination. In the rectovaginal examination, a doctor or other health care provider places one finger in the vagina and another in the rectum to assess the rectovaginal septum. The examiner will look for any scarring or masses that may indicate cancer or another disease. Typically, a rectovaginal examination is performed to assess pelvic pain, rectal symptoms, or a pelvic mass. It can also provide a sample for fecal occult blood testing.
Fecal Immunochemical Test (FIT) is a diagnostic technique that examines stool samples for traces of non-visible blood, which could potentially indicate conditions including bowel cancer. Symptoms which could be caused by bowel cancer and suggest a FIT include a change in bowel habit, anaemia, unexplained weight loss, and abdominal pain. By using a random forest classification model, sensitivity can be increased.
Serrated polyposis syndrome (SPS), previously known as hyperplastic polyposis syndrome, is a disorder characterized by the appearance of serrated polyps in the colon. While serrated polyposis syndrome does not cause symptoms, the condition is associated with a higher risk of colorectal cancer (CRC). The lifelong risk of CRC is between 25 and 40%. SPS is the most common polyposis syndrome affecting the colon, but is under recognized due to a lack of systemic long term monitoring. Diagnosis requires colonoscopy, and is defined by the presence of either of two criteria: ≥5 serrated lesions/polyps proximal to the rectum, or >20 serrated lesions/polyps of any size distributed throughout the colon with 5 proximal to the rectum.
| Authority control databases: National |
|---|
