[Pilot test for Helicobacter pylori detection with ammonia breath test]

In Argentina we have little access to the more sensitive and specific non-invasive diagnostic methods for the detection of Helicobacter pylori (HP), such as the urea breath test. The upper gastrointestinal videoendoscopy, with biopsy for histological analysis and rapid urease test remains as the usual method in our country, but the cost is high and the accessibility is also limited. For this reason we propose to develop a new fast, accurate, accessible and inexpensive method for measuring the concentration of expired NH in order to achieve a diagnosis of active infection.

To determine the utility of a non-invasive method for detecting HP through the measurement of ammonia in the breathing.

We studied 3 patients older than 21 years, attending the Gastroenterology clinic. All patients who meet the inclusion criteria were evaluated with an upper gastrointestinal videoendoscopy and gastric biopsies (antrum, body and incisura angularis). Samples were analyzed by histopathological examination and urease test. The subjects with both negative tests (non-infected) or positive (infected) were selected for ammonia measurement in exhaled air.

The prevalence of HP infection was 60.9% (14 patients). Ten of these patients had significant differences between the baseline ammonia and the ammonia after urea ingestion, yielding a specifcity of 88.9% and a sensitivity of 71.43%, with a Jouden index higher than 50%.

Although the experience must be carried forward, the results of this pilot study suggest that the measurement of ammonia in breath test after ingestion of unmarked urea would be applicable as a diagnostic test for HP, taking into account its low cost and easy management compared to conventional non-invasive methods.