Evaluation of a new enzyme immunoassay for the detection of Helicobacter pylori in stool specimens.

H. pylori infects the gastric mucosa and causes many digestive disorders such as peptic ulcer, chronic gastritis and gastric cancer. H. pylori infection relates neither to functional health status, nor to intensity of dyspepsia. There is evidence that in most patients with H. pylori positive functional dyspepsia do not improve with eradication of the organism.This study evaluated the diagnostic accuracy of HpSA by determining the sensitivity and specificity of the stool antigen test in predicting successful eradication during and after anti microbial therapy. The work was conducted on patients who underwent upper gastrointestinal endoscopy at Al-Azhar University hospitals. Fifty patients (34 male & 16 female) with dyspepsia were selected, the exclusion criteria included use of antibiotics and proton pump inhibitors up to one month before the study. All cases were submitted to, full history, general and local examination and upper gastrointestinal endoscopy. Biopsies were taken from the antrum and body of the stomach for rapid urease test and histopathology. Stool samples were taken to detect H. pylori stool antigen. Positive patients received eradication treatment for one month and H. pylori status was re-determined by rapid urease test, histological examination and HpSA test one month later. H. pylori was detected by rapid urease test in 29 (58%) dyspeptic patient by histology in 26(52%) dyspeptic patient, while H. pylori was detected by HpSA immunoassay in 16 (32%) dyspeptic patient. The sensitivity and specificity of HpSA were 57.7% and 95.8% respectively. After successful eradication of H. pylori, reassessment by rapid urease test and histology revealed curative rate of 86.2% and 84.6% respectively, while HpSA immunoassay revealed curative rate 75%. Based on these results, the HpSA immunoassay gave sensitivity (75%) and specificity (100%). The H. pylori stool test represents an accurate and novel non-invasive concept for diagnosis of infection and can be used for daily routine in clinical practice. HpSA is a promising non-invasive test for diagnosis of H. pylori infection but may be hampered by low patient acceptability. So, HpSA is a valuable test in the pre-and post eradication assessment of infection. HpSA can be profitably employed in the primary diagnosis of H. pylori infection. This non invasive test could be very useful in investigating dyspeptic young patients. Also, it could be used profitably in epidemiological studies to determine the prevalence of H. pylori infection in the asymptomatic subjects in different communities.