| 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 |
Astool 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 andfecal immunochemical test are the most common stool tests to diagnose many conditions that caused by bleeding in thegastrointestinal system, includingcolorectal cancer orstomach cancer.[2] The American College of Gastroenterology has recommended the abandoning of gFOBT testing as a colorectal cancer screening tool, in favor of thefecal immunochemical test (FIT).[3] The newer and recommended tests look forglobin,DNA, or other blood factors includingtransferrin, while conventionalstool guaiac tests look forheme.
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]
TheAmerican Cancer Society and theU.S. Preventive Services Task Force recommended colorectal cancer screening with afecal immunochemical test every year, or a multi-target stool DNA test for every three years from the age of 45.[5] Other options include asigmoidoscopy orvirtual colonoscopy (CT colonography) for every five years or acolonoscopy 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] TheNational Committee for Quality Assurance (NCQA) issued an update to theHealthcare 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 lesscost effective compared to colonoscopy or fecal occult blood testing.[9] Three-year multi-target stool DNA test has been estimated to cost $11,313 perquality-adjusted life year (QALY) compared with no screening.[10]
Parasitic diseases such asascariasis,hookworm,strongyloidiasis andwhipworm 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 asClostridioides difficile (C. diff) can also be identified. Viruses such asrotavirus can also be found in stools.[11] Other stool tests involve the detection of antibiotic resistance as to guide appropriate therapy, e.g. Clarithromycin resistance ofHelicobacter pylori represents a major challenge in eradication therapy but the responsible bacterial genomic markers can be detected in stool using PCR technology and thus can guide the prescription of the appropriate antibiotics to specific patients.[12]
Afecal pH test may be used to determinelactose intolerance or the presence of an infection.[13]Steatorrhea can be diagnosed using afecal fat test, which checks for the malabsorption of fat.[14]
Faecal elastase levels are becoming the mainstay of pancreatitis diagnosis.
Authority control databases: National |
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