Urea breath test | |
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Intervention | |
ICD-9-CM | 89.39 |
The urea breath test is a rapid diagnostic procedure used to identify infections by Helicobacter pylori, a spiral bacterium implicated in gastritis, gastric ulcer, and peptic ulcer disease. It is based upon the ability of H. pylori to convert urea to ammonia and carbon dioxide. Urea breath tests are recommended in leading society guidelines as a preferred non-invasive choice for detecting H. pylori before and after treatment.
Patients swallow urea labelled with an uncommon isotope, either radioactive carbon-14 or non-radioactive carbon-13. In the subsequent 10–30 minutes, the detection of isotope-labelled carbon dioxide in exhaled breath indicates that the urea was split; this indicates that urease (the enzyme that H. pylori uses to metabolize urea) is present in the stomach, and hence that H. pylori bacteria are present.
For the two different forms of urea, different instrumentation is required. Carbon-14 is normally measured by scintillation, whereas carbon-13 can be detected by isotope ratio mass spectrometry or by mass correlation spectrometry. For each of these methods, a baseline breath sample is required before taking the isotope-labeled urea, for comparison with the post-urea sample, with a 20- to 30-minute duration between them. Samples may be sent to a reference laboratory for analysis. Alternatively, mass correlation spectrometry can be performed as an office-based test since breath samples are continuously collected, and results are provided immediately within minutes.