The implementation | The Urease Rapid Test

The implementation

The patient is first prepared for the gastroscopy. For the examination, the throat is first anaesthetized. If desired, the patient can also be given medication that has a calming effect and takes away the fear of the examination.

Then the doctor examines the throat and the stomach mucosa with a special device (so-called endoscope). He then removes a small piece of tissue from a place that seems suspicious to him. The removed tissue is then placed on a special culture medium.

This culture medium contains mainly urea, which can be split by the bacterial urease enzyme. In addition, this nutrient medium contains a color indicator solution that changes over when the pH value changes. This means that when urea is split, ammonia is produced, which leads to a change in the pH-value and this can be detected by color.

The evaluation

The evaluation of this test is quite simple – the test is based on a change in the pH value. This change is indicated by a color change. A red color change indicates a positive result, whereas a yellow color change indicates a negative result.

The Urease Rapid Test is a relatively reliable test with high sensitivity and specificity. However, the result can be falsified if the enzyme activity is inhibited. This can be caused by taking proton pump inhibitors or antibiotics. For this reason, the use of proton pump inhibitors should be stopped one week before the test and antibiotics six weeks before.

Can the rapid test also be false positive?

The test may also be positive, even if you do not have a Helicobacter pylori infection. This can occur when the stomach is overgrown with another bacterium. Usually two positive test results or a positive histological examination are required for a diagnosis. In a histological examination, the removed tissue is examined more closely under a microscope. If the bacteria can be detected here, one suffers from an infection with Helicobacter pylori, which must be treated.