Stool immunoassay for Helicobacter pylori is not specific enoughBMJ 2000; 320 doi: https://doi.org/10.1136/bmj.320.7248.1541 (Published 03 June 2000) Cite this as: BMJ 2000;320:1541
- Mario Guslandi, gastroenterologist. ()
EDITOR—The paper by Lehmann et al 1 confirms the view that stool immunoassay for Helicobacter pylori is a non-invasive, cheap, and reliable test for assessing H pylori infection in unselected patients. However, Lehmann et al overlook the major issue concerning this diagnostic tool—namely, whether it is suitable for evaluating the outcome of treatment.
Although some authors, such as Vaira et al, maintain that the test has a high specificity only four weeks after the end of the treatment,2 others report a number of false positive results after eradication. In particular, when the test is performed even two months after the eradication of H pylori, it still shows an unsatisfactory specificity, with 18% false positive results.3
In defending their findings, Vaira et al seek support from recent studies, which are unpublished and therefore not available for evaluation.2 Thus, for the time being, we must draw on the published information. Data presented at the recent international workshop of the European Helicobacter pylori Study Group held in Helsinki confirm that in treated patients the specificity of stool immunoassay for Helicobacter pylori is lower than that of the C13 urea breath test, indicating that even six months after eradication the number of false positives is high.4 5