Urea breath test

Abstract

The urea breath test (UBT) is a noninvasive, 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 (high sensitivity, 90-100 % and specificity, 90-100 %). This test is based on the organism's urease activity, which liberates carbon dioxide (CO2) from urea and produces ammonia to buffer its acidic environment. Ingestion of labeled urea results in the production of labeled CO2 which then can be detected in the breath. Urea can be labeled with two different isotopes, 2 4C (the radioactive isotope) or 2 3C (the nonradioactive stable isotope). The methodology of the UBT have been changed including the dose of labeled urea used, the type of test meal, the time of breath collection, the cutoff values, and the equipment adopted to measure isotope enrichment. However, a definitive standardization of this test does not yet exist, and a unique and generally proposed cutoff level is not possible because it has to be adapted to different factors.