Also known as rapid urease test, a CLO test is a test that is used to determine the presence of Helicobacter pylori. The test involves placing a biopsy sample on a gel that contains buffers, phenol red, pH indicator and urea or a reaction strip.
If there is a presence of Helicobacter pylori, the pH indicator color will change. This test is usually carried out quickly and its not costly, as stated by Mayo Clinic. The results of the test may take up to 3 hours to be interpreted. Early preparation is required, as a patient should stop using antibiotics for three weeks prior to the test, as stated by TRI-MED.