VALIDATION OF A NEW SALIVA TEST FOR HELICOBACTER-PYLORI INFECTION

The purpose of this study was to evaluate a recently introduced saliva test measuring immunoglobulin (Ig) G antibodies to Helicobacter pylor i by enzyme-linked immunosorbent (ELISA). ELISA has previously been va lidated against IgG serological tests; however, it is not considered t he definitive test for H pylori infection. Using endoscopic antral bio psies as the 'gold standard' for comparison, the saliva test was valid ated on 70 patients with upper gastrointestinal symptoms admitted to S t. Paul's Hospital Gastroenterology Clinic for gastroduodenoscopy. Thi rty-five patients (50%) had histological evidence of gastritis and, by using acridine orange stain, the bacterium was visualized in 25 patie nts (71%). A biopsy was considered positive when the bacterium was vis ualized. The saliva test was determined to be 80% sensitive and 80% sp ecific for H pylori infection when the cut-off for a positive test was 0.3 ELISA U/mL. Positive and negative predictive values were 69% and 88%, respectively. More study is required to assess the clinical utili ty of the test.