EVALUATION OF SALIVARY ANTIBODIES TO DETECT INFECTION WITH HELICOBACTER-PYLORI

Helicobacter pylori infection is an important cause of peptic ulcer di sease and chronic gastritis. Infection with this bacterium stimulates the production of immunoglobulin (Ig) G antibody. Salivary IgG antibod y tests to detect H pylori infection offer a convenient and noninvasiv e method of diagnosis. To evaluate an IgG salivary antibody kit, saliv a was collected from 157 out-patients with dyspepsia referred for endo scopy to a tertiary centre. A salivary IgG ELISA antibody assay was pe rformed using the Helisal Helicobacter pylori (IgG) assay kit, and at least four gastric biopsies were obtained. H pylori infection was conf irmed by demonstration of the organism on Warthin-Starry silver stain (sensitivity 85%, specificity 55%). The prevalence of infection with H pylori was 30%. When the analysis was redone, excluding those treated with eradication therapy, the results were similar (sensitivity 86%, specificity 58%). The positive predictive value of the assay was 45% a nd the negative predictive value was 90%. Despite the ease of sampling , the assay used has limited diagnostic utility, lacking the predictiv e value to indicate which patients referred with dyspeptic symptoms to a tertiary care setting are infected with H pylori.