Occult Blood and Helicobacter pylori Antigen Stool Test- Test Result, Unit, Normal Range, Test Method, and Clinical Significance

Introduction of Occult Blood and Helicobacter pylori Antigen Stool Test

Occult Blood and Helicobacter pylori Antigen Stool Tests are clinically important for the diagnosis of diseases. Fecal occult blood test positive is common in hookworm infestation. H. pylori antigen stool test is clear from the title of the assay. Both tests are rapid and easy to perform in a simple setup of the clinical laboratory. In both assays stool/ feces is tested and a report can be dispatched within an hour. Tests work in the principle of Immunochromatography.

Occult Blood and H. pylori Antigen Stool Test-Test Result and Test Method

Keynotes on Occult Blood and H. pylori Antigen Stool Test

• The commonest causes of positive occult blood in tropical countries include parasitic infection (hookworm) and gastrointestinal disorders such as colitis, polyps, and diverticulitis.
• The principle of the test-In the ‘Facal Occult Blood (FOB)Test’, oxygen is produced when the hemoglobin in the blood reaches contact with hydrogen peroxide (H2O2) the liberated oxygen reacts with a chromogen (aminopyrine) to yield a blue color.

• The Fecal Occult Blood test in short is also called the FOB test.
• In the case of a positive test, additional testing such as a colonoscopy is needed to locate the source of the bleeding.
• Helicobacter pylori is an s-shaped or curved gram-negative bacillus measuring 1.5-3.5 µm in length and 0.5-0.9µm in width. It is motile by a tuft of flagella up to 4-7 sheathed flagella at one end and are non-spring. It may be changed into the coccal form on exposure to air within 2 hours. It is microaerophilic, non-saccharolytic, and rich in oxidase, catalase, and urease enzyme. Guanine -cytosine content of DNA is 35.2 mol %.
• Drug resistance is a growing problem in H. pylori treatment and thus asymptomatic colonization treatment should be avoided.
• Histology is the “Gold standard” in routine hospital diagnostics with sensitivity and specificity >95% whereas the urea breath test is an alternative gold standard also with sensitivity and specificity >95%.