UREA BREATH TEST – ITS ROLE IN DIAGNOSTICS
Background. Each year many patients visit their physicians complaining of digestive symptoms, most commonly functional dyspepsia (»indigestion«) or gastroesophageal reflux (»heartburn«). However, many patients with abdominal discomfort are actually suffering from gastric or duodenal ulcers that are commonly caused by H. pylori and thus are curable. Clearing the infection usually heals the ulcer and prevents relapse, so an accurate diagnosis is important. There are several options for diagnosing H. pylori infection: serology to detect antibodies against the bacterium; endoscopic biopsy for urease testing (H. pylori produce a urease that breaks down urea to ammonia and carbon dioxide); histology with special stains; or culture. Unfortunately, these procedures are invasive, expensive and not always accurate. Serological tests require a blood sample and tell only that a patient has been exposed to H. pylori at some time in the past, but not whether the patient is currently infected. Endoscopy and biopsy can detect current infection — the CLO test urease test allows rapid detection of H. pylori in gastric biopsy specimens — but endoscopy and biopsy are unpleasant medical procedures.
Recently, noninvasive, sensitive, specific, easy to perform and patient’s well accepted methods had been developed known as urea breath test (UBT). When an infected person swallows a dose of urea labeled with an isotope of carbon — carbon-13 (13C) or carbon-14 (14C) – H. pylori in the gastric mucosa break down the labeled urea to form ammonia and labeled carbon dioxide. The carbon dioxide is absorbed into the bloodstream and excreted via the lungs. The patient then exhales into a device that measures the level of carbon dioxide. The urea breath test is specific for H. pylori (it detects only urease-producing bacteria), it is sensitive (the labeled urea reaches a large area of the stomach and thus reflects total gastric urease activity) and the results can be reproduced.
Conclusions. Invasive and noninvasive diagnostic tests for H. pylori are described. In a more detailed frame UBT is presented, the test which is recomended in certain instances by European Gastroenterologic Society. The UBT should be available for use in the doctor’s office to provide a rapid diagnosis.
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