H – Pylori Tests
The Helicobacter pylori infection must be diagnosed and treated when its existence is suspected in order to avoid serious complications in the patient’s health. Nowadays, there are many tests and techniques that can help to diagnose this infection; however, some of them are less invasive and uncomfortable for the patient than others and must be selected according to each patient’s characteristics and needs.
One of the less invasive tests is the detection of antibodies in the blood, which consists in detecting the presence of specific antibodies to H. pylori in a patient’s blood sample. This test has a the disadvantage in the difficulty to differentiate between an active infection and a treated one because the H. pylori antibodies title may remain at high levels in the patient’s blood for a long time after receiving a correct treatment.
Therefore, in most cases when this test has a positive result, the doctor can indicate a second test to confirm an active infection. However, when this test is negative, it is very unlikely that the patient has or had had an H. pylori infection.
Another common test used to detect H. pylori infection is the urea breath test. It consists in giving the patient tagged carbon molecules in an edible presentation (like a pill, liquid or pudding). If these carbon molecules are broken in the stomach and released through the breath, it means that the patient has a Helicobacter infection.
When this test is positive, it indicates that the patient has an active infection that can be a new one or a treatment-resistant infection. It is important to know that antacid medication (like PPIs, Pepto-Bismol) and some antibiotics can alter the result of the test, so the patient must lay off those kinds of treatments some days before undergoing the test.
The last noninvasive test to diagnose H. pylori infection is the stool antigen test. This test consists in looking for the antigens (foreign proteins) specific for H. pylori in the patient’s stool. It can be used both to detect a new infection or check the effectiveness of the treatment. As in the breath test, some antacids and antibiotics can alter the test result, so the patient must stop taking them a few days before undergoing the test.
Regarding the invasive tests, they refer to tests that need using an endoscope to be performed. In some cases, the patient must be sedated to introduce a long tube with a tiny specialized camera (endoscope) through the mouth and the esophagus until reaching the stomach and duodenum.
The camera allows seeing the stomach and duodenum epithelium and detecting any irregularity on it (like ulcers). Once the endoscope is in the stomach, tissue samples (biopsy) can be taken and subsequently examined to determine the presence of H. pylori.
One of these techniques to analyze the tissue sample obtained is the histology, which consists in examining all the cells with a microscope to observe the H. pylori or any other disease that may explain the patient’s signs and symptoms.
In the tissue obtained, the urease enzyme can also be detected, which is produced by the Helicobacter to survive in acids environments. Likewise, the tissue can be cultured in a laboratory to evaluate the efficacy of different antibiotics in the antibacterial treatment.
Finally, a PCR (polymerase chain reaction) study can be done in the tissue sample obtained to detect the fragments of H. pylori DNA and prove the infection.