COMPARISON OF COMMERCIAL DIAGNOSTIC-TESTS FOR HELICOBACTER-PYLORI ANTIBODIES

A number of serological tests measuring the presence of Helicobacter p ylori-specific serum immunoglobulin G (IgG) are now commercially avail able. The aim of this study was to evaluate the clinical accuracy of f ive commercial H. pylori antibody tests: GAP-IgG (Biomerica), HELpTEST (AMRAD, Kew, Victoria, Australia), HELICO-G (Porton Cambridge), Pylor iset (Orion Diagnostica), and ROCHE (Roche Diagnostics). A total of 16 2 subjects presenting for routine upper endoscopy were studied. H. pyl ori was diagnosed if culture, histology, or both were positive. Ten mi lliliters of venous blood was collected at the time of endoscopy for s erological assessment. The sensitivity and specificity of each test (G AP-IgG, HELpTEST, HELICO-G, Pyloriset, and ROCHE) were as follows: 83 and 79%, 92 and 77%, 86 and 65%, 89 and 56%, and 98 and 69%, respectiv ely. Positive and negative predictive values were 97 and 83%, 90 and 9 1%, 76 and 83%, 68 and 84%, and 86 and 97%, respectively. The specific ity of most tests increased by approximately 10% when sera from subjec ts less than 45 years old were examined. The number of sera falling in to the grey zone for each test (an indeterminate result with respect t o H. pylori status) varied between 2.5 and 19%. This study highlights the need for all serological kits to be independently evaluated on the population to be studied by testing against a microbiologically defin ed panel of H. pylori-positive and -negative sera.