Review article: ¹³C‐urea breath test in the diagnosis of Helicobacter pylori infection – a critical review

Abstract

SUMMARYThe urea breath test is a non-invasive, simple and safe test which provides excellent accuracy both for the initial diagnosis of Helicobacter pylori infection and for the confirmation of its eradication after treatment. Some studies have found no differences between urea breath test performed under non-fasting conditions. The simplicity, good tolerance and economy of the citric acid test meal probably make its systematic use advisable. The urea breath test protocol may be performed with relatively low doses (<100 mg) of urea: 75 mg or even 50 mg seem to be sufficient. With the most widely used protocol (with citric acid and 75 mg of urea), excellent accuracy is obtained when breath samples are collected as early as 10-15 min after urea ingestion. A unique and generally proposed cut-off level is not possible because it has to be adapted to different factors, such as the test meal, the dose and type of urea, or the pre-/post-treatment setting. Fortunately, because positive and negative urea breath test results tend to cluster outside of the range between 2 and 5&, a change in cut-off value within this range would be expected to have little effect on clinical accuracy of the test.

3rd BRAZILIAN CONSENSUS ON Helicobacter pylori

“…False-positive results are seldom observed and may occur in patients undergoing surgery for gastric resection or individuals with oral flora rich in urease producing microorganisms retaining ingested urea in the oral cavity for a long time before swallowing (71) . Individuals infected by H pylori develop specific antibodies in the serum against this microorganism.…”

“…The 13 C-urea breath test is now universally accepted as the gold standard method for diagnosing and monitoring treatment of H pylori infection in adults and children over 6 years old, with sensitivity and specificity always higher than 95% (71) . The test was validated for adults in Brazil on 1999 (26) and for adolescents and children on 2002 (106) .…”

Helicobacter pylori – Not Only a Gastric Pathogene?

“…adhesins, which help H. pylori to adhere to mucosal epithelial cells (Gisbert and Pajares 2004). Important is BabA protein which binds Lewis b antigen, which is present in individuals with 0 blood group.…”

Management ofHelicobacter pyloriinfection

“…In the presence of H. pylori, the ingestion of urea, labeled with either the nonradioactive isotope 13 C or the radioactive isotope 14 C, results in production of labeled CO 2 , which can be quantitated in expired breath (87)(88)(89)(90). Although the amount of radiation in the 14 C UBT is less than daily background radiation exposure (88), the 13 C test is preferred in children and pregnant females (87). Overall, the performance characteristics of both tests are similar with sensitivity and specificity typically exceeding 95% in most studies (87,88).…”