Laboratory and microbiological tests
Helicobacter pylori tests
What is Helicobacter pylori?
Helicobacter pylori (H. pylori) is a bacterium that lives in the stomach. It can cause chronic gastritis, stomach and duodenal ulcers and, in some people, increase the risk of stomach cancer. When an infection is detected, treatment with antibiotics is usually prescribed.
Several testing methods are used to detect the infection and assess the effectiveness of treatment. The H. pylori stool antigen test is the most commonly performed test in Lithuania. Some healthcare facilities also perform the ¹³C urea breath test. If a gastroscopy is performed, the bacterium can be detected by examining biopsies of the stomach lining. Your doctor will decide which test is most appropriate.
- Do not take antibiotics or bismuth preparations for 4 weeks before the test.
- Do not take proton pump inhibitors (PPIs), such as omeprazole, pantoprazole, esomeprazole, lansoprazole or rabeprazole, for 2 weeks before the test.
- If you take H₂ receptor blockers (such as famotidine), it is recommended that you stop taking them 24–48 hours before the test.
- Always discuss any changes to your medication with your doctor.
- If you experience heartburn during this period, you can usually take antacids or alginates, but consult your doctor before using them.
a) H. pylori stool antigen test
What is it?
This is a reliable, non-invasive test that detects H. pylori antigens in a stool sample. It is widely used both for the initial diagnosis of infection and to assess the effectiveness of treatment.
How should I prepare?
- No special diet is required.
- The general recommendations regarding medication apply.
- The sample must be collected in a special container according to the laboratory’s instructions.
- The test is not recommended if you have severe diarrhoea or gastrointestinal bleeding.
b) Testing during gastroscopy
What is it?
During a gastroscopy, your doctor may take small samples of the stomach lining (biopsies). A rapid urease test, histological examination or other laboratory tests may then be performed on these samples to detect H. pylori infection.
If a gastroscopy is performed for other reasons (such as inflammation of the stomach, an ulcer, anaemia, polyps or other changes to the stomach lining), H. pylori can also be detected in the biopsies taken during the procedure, so an additional test is often unnecessary.
How should I prepare?
- Preparation is the same as for a gastroscopy.
- Following the general recommendations regarding medication is important for the accuracy of the test.
c) ¹³C urea breath test
What is it?
This is one of the most accurate non-invasive methods for detecting H. pylori. It can be used both to diagnose the infection and to assess the effectiveness of treatment, but it is not available at every healthcare facility in Lithuania.
How should I prepare?
- Do not eat for at least 6 hours before the test.
- Do not smoke or chew gum on the morning of the test.
- During the test, you will drink a special solution and then blow into sample collection bags or tubes several times.
- The test usually takes approximately 20–30 minutes.
d) Blood antibody test
What is it?
This blood test detects antibodies against H. pylori.
Important to know
- No special preparation is required.
- You do not need to stop taking any medication.
- The test cannot distinguish a current infection from a previous infection. It is therefore unsuitable for assessing the effectiveness of treatment and is now used much less frequently.
e) H. pylori culture and antibiotic susceptibility testing
What is it?
If H. pylori has not been successfully eradicated after two or more appropriately completed courses of treatment, biopsies may be taken during a gastroscopy for bacterial culture and antibiotic susceptibility testing (an antibiogram). Some laboratories also perform molecular tests that can identify the bacterium’s resistance to certain antibiotics.
Why is it performed?
- It helps determine the most effective treatment based on the specific bacterium’s susceptibility to antibiotics.
- It is recommended for patients whose previous eradication treatments have been unsuccessful.
After treatment
The eradication of H. pylori should be confirmed using a stool antigen test or a ¹³C urea breath test. The test should be performed no earlier than 4 weeks after completing the course of antibiotics, and proton pump inhibitors must be stopped for at least 2 weeks before the test.