CLO TEST
The CLO test (Campylobacter-Like Organism test), also known as a rapid urease test (RUT), is an endoscopic diagnostic tool used to detect the presence of Helicobacter pylori (H. pylori) bacteria in the stomach lining.
No fasting needed
Take regular medicines as usual
Wear comfortable, loose clothing (you’ll change into a gown)
No special restrictions
It is a fast, highly sensitive, and specific method for identifying the bacteria responsible for gastritis, gastric ulcers, and duodenal ulcers.
Key Aspects of the CLO Test Presentation
- Procedure: During a gastroscopy (endoscopy), a small tissue sample (biopsy) is taken from the antrum of the stomach and placed into a plastic slide containing a gel medium.
- Mechanism: The gel contains urea and a pH indicator (phenol red). If H. pylori is present in the tissue, the urease enzyme produced by the bacteria converts urea into ammonia.
- Result Interpretation:
- Positive: The ammonia raises the pH, causing the gel to change color from yellow to magenta (purple-red).
- Timeframe: 75% of positive tests change color within 20 minutes; however, results should be read up to 24 hours.
- Accuracy: The test has a high sensitivity (around 85-98%) and specificity (up to 98%), making it a reliable, rapid diagnostic tool.
- Advantages: It is rapid, inexpensive, and easy to perform directly in the endoscopy suite.
- Limitations: False negatives can occur if the patient is taking Proton Pump Inhibitors (PPIs) or antibiotics. It is recommended to stop these medications 2 weeks prior to the test.
Clinical Significance
The CLO test plays a crucial role in managing gastrointestinal conditions by confirming H. pylori infection, aiding in pre-surgical decisions, and guiding post-surgical management.
Alternatives
If the CLO test is not available or if the patient cannot undergo endoscopy, other tests include the Urea Breath Test (UBT), stool antigen test, or histological examination of gastric tissue.