CLO test and Dyspepsia - Why the CLO test is the Gold standard in Diagnosing H. Pylori and the significance PDF

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Why the CLO test is the Gold standard in Diagnosing H. Pylori and the significance of this test in patients presenting with dyspepsia....

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Name: Rishan Charles A/L Razali Student ID: 0323663 Semester: 6 Date of Posting: 9/3/2020 – 3/4/2020 Topic: Describe the clinical usage of CLO test and principle in dyspepsia patients.

Describe the clinical usage of CLO test & principle in dyspepsia patients CLO stands for Campylobacter-like organism and is also known as the Rapid Urease test. This diagnostic test is used for the detection of Helicobacter pylori by finding the presence of urease. Urease is an enzyme that is produced by Helicobacter pylori, and thus the presence of the infection can easily be identified using a colorimetric test based on the pH change when urea is hydrolyzed into ammonia and CO2. Helicobacter pylori, or H. pylori, previously called Campylobacter Pylori, are stomach bacteria that can cause the development of ulcers. It has been proven that most duodenal ulcers and about two-thirds of gastric ulcers have been attributed to H. pylori infection. Some diseases that are associated with H. pylori are, peptic ulcer disease, duodenal ulcer, stomach carcinoma, erosive gastritis, mucosa-associated lymphoid tissue (MALT) lymphoma as well as gut-associated lymphoid tissue (GALT) lymphoma. The CLO testing is performed during an endoscopy. The scope used for the endoscopy will search your stomach for any type of visible damage, and if any is found, the CLO test will be conducted. The CLO test is a simple test that enables a rapid diagnosis. The CLO test is a sealed plastic slide holding an agar gel that contains urea, a pH indicator, phenol red, buffers, and bacteriostatic agents that help prevent false colour changes that could lead to false-positive readings. If the urease enzyme of H. pylori is present in an inserted tissue sample, the resulting degradation of urea causes the pH to rise, and the colour of the gel turns from yellow to a bright magenta colour. The sensitivity and specificity of biopsy urease tests are approximately 90% to 95% and 95% to 100%, respectively. Because a positive rapid urease test is based on the bacterial load in the gastric biopsy, when obtaining tissue samples from the antrum and the corpus, use of large forceps or multiple samples increases the sensitivity of the test. Recent gastrointestinal bleeding, use of PPIs and/or antibiotics and/or bismuth-containing compounds, and presence of atrophic gastritis and/or diffuse intestinal metaplasia may result in false negative test. False positive tests are unusual. However, mouth flora may produce urease and contaminate samples. It is important for the endoscopist to take specimens from macroscopically normal mucosa as H. pylori colonize healthy gastric tissue and biopsies obtained from abnormally appearing mucosa (e.g., intestinal metaplasia) or from lesion margins are often negative. The CLO testing is usually ordered if you are experiencing symptoms that could indicate the presence of a stomach ulcer, such as pain, nausea, bloating, belching or dyspepsia. H. pylori infection should be screened in patients with history of, or active, peptic ulcer disease, those with a low-grade gastric mucosa-associated lymphoid tissue lymphoma, and in the evaluation of dyspeptic symptoms. A “test-and-treat strategy” has been recommended for detecting and eradicating H. pylori in patients presenting with dyspepsia with a low gastric cancer risk. The most recent version of this strategy targets patients younger than 60 years with chronic or frequent recurring epigastric pain or discomfort in the absence of alarm symptoms (Red flags), such as unexplained weight loss, progressive dysphagia, odynophagia, recurrent vomiting, family history of gastrointestinal cancer, and iron deficiency anaemia. Moreover, if a patient with dyspepsia undergoes endoscopy, H. pylori presence should be evaluated in gastric biopsies such as the biopsy urease testing, with the intention of treating if present.

Algorithm for dyspepsia management. EGD = esophagogastroduodenoscopy; PPI = proton pump inhibitor.

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