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Stool test

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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.
Purposediagnose if medical condition is present

Astool testis 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.

Collection[edit]

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]

Visual examination[edit]

The patient and/or health care worker in the office or at the bedside is able to make some important observations.

  • Color
  • Texture/consistency—formed
  • Classify type of feces (diagnostic triad for irritable bowel syndrome) based onBristol stool scale

Cancer screening[edit]

Fecal occult blood testandfecal immunochemical testare the most common stool tests to diagnose many conditions that caused by bleeding in thegastrointestinal system,includingcolorectal cancerorstomach 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 testslook 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 Societyand theU.S. Preventive Services Task Forcerecommended colorectal cancer screening with afecal immunochemical testevery year, or a multi-target stool DNA test for every three years from the age of 45.[5]Other options include asigmoidoscopyorvirtual colonoscopy(CT colonography) for every five years or acolonoscopyfor every 10 years. Fecal occult blood testis 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 effectivecompared 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]

Microbiology tests[edit]

See also:Kato technique

Parasitic diseases such asascariasis,hookworm,strongyloidiasisandwhipwormcan 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 asClostridium difficile( "C. diff." ) can also be identified. Viruses such asrotaviruscan 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 pylorirepresents 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].

Chemical tests[edit]

Afecal pH testmay be used to determinelactose intoleranceor the presence of an infection.[13]Steatorrheacan be diagnosed using afecal fattest, which checks for the malabsorption of fat.[14]

Faecal elastase levels are becoming the mainstay of pancreatitis diagnosis.

See also[edit]

References[edit]

  1. ^"Approach to stool microscopy".medilib(in Persian). 2021-06-02.Retrieved2022-08-16.
  2. ^"Fecal Occult Blood Test (FOBT)".
  3. ^Rex DK, Johnson DA, Anderson JC, Schoenfeld PS, Burke CA, Inadomi JM (March 2009)."American College of Gastroenterology guidelines for colorectal cancer screening 2009 [corrected]".The American Journal of Gastroenterology.104(3): 739–750.doi:10.1038/ajg.2009.104.PMID19240699.S2CID295873.
  4. ^abOsborn NK, Ahlquist DA (2005)."Stool screening for colorectal cancer: molecular approaches".Gastroenterology.128(1): 192–206.doi:10.1053/j.gastro.2004.10.041.PMID15633136.
  5. ^abTepus M, Yau TO (20 May 2020)."Non-Invasive Colorectal Cancer Screening: An Overview".Gastrointestinal Tumors.7(3): 62–73.doi:10.1159/000507701.PMC7445682.PMID32903904.
  6. ^"American Cancer Society recommendations for colorectal cancer early detection".www.cancer.org.Archived fromthe originalon 3 December 2016.Retrieved14 July2016.
  7. ^National Committee for Quality Assurance."Healthcare Effectiveness Data and Information Set 2017 Volume 2: Technical Update"(PDF).
  8. ^"FDA approves first non-invasive DNA screening test for colorectal cancer [press release]".Food and Drug Administration.August 11, 2014.Retrieved30 June2015.
  9. ^Barzi A, Lenz HJ, Quinn DI, Sadeghi S (1 May 2017)."Comparative effectiveness of screening strategies for colorectal cancer".Cancer.123(9): 1516–1527.doi:10.1002/cncr.30518.PMC6879196.PMID28117881.
  10. ^Berger BM, Shroy PC, Dinh TA (2015)."Screening for Colorectal Cancer Using a Multitarget Stool DNA Test: Modeling the Effect of the Intertest Interval on Clinical Effectiveness".Clinical Colorectal Cancer.15(3): e65–e74.doi:10.1016/j.clcc.2015.12.003.PMID26792032.
  11. ^"Stool culture".
  12. ^Mommersteeg MC, Nieuwenburg SA, Wolters LM, Roovers BH, van Vuuren HA, Verhaar AP, Bruno MJ, Kuipers EJ, Peppelenbosch MP, Spaander MC, Fuhler GM (November 2023)."The use of non-invasive stool tests for verification of Helicobacter pylori eradication and clarithromycin resistance".United European Gastroenterol J.11(9): e894-903.doi:10.1002/ueg2.12473.PMC10637120.PMID37854002.
  13. ^"Stool Acidity Test - MedicineNet.com".
  14. ^"MedlinePlus Medical Encyclopedia: Fecal fat".
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