SERODIAGNOSIS OF HELICOBACTER-PYLORI INFECTION - AN EVALUATION OF A COMMERCIALLY AVAILABLE ELISA-IGG

Background: Our aim was to evaluate a commercially available ELISA (Py loriset(C) IgG, Orion diagnostica, Imphos B.V.) for detection of serum IgG antibodies to Helicobacter pylori. Methods: Serum samples were ta ken from 154 Dutch patients. As a reference method several biopsy spec imens were taken from different gastric areas for histological analysi s, bacterial culture and direct urease testing. The sensitivity, speci ficity, positive and negative predictive values of the Pyloriset(R) Ig G were calculated as compared to the reference method. Results: Of 154 patients 126 were found to be H. pylori positive (82%), 28 were H. py lori negative (18%). Using a cut-off value at a titre of 500 U/l (as a dvised by the manufacturer) we found a sensitivity, specificity, posit ive predictive value (PPV) and negative predictive value (NPV) of 81, 89, 97 and 51%, respectively. Lowering the cut-off value to 350 U/l an d excluding patients aged above 70 years optimalized the performance o f the Pyloriset(R) IgG to a sensitivity, specificity, PPV and NPV of 9 2, 96, 99 and 72%, respectively. In the subgroup of 54 patients under the age of 45 years a sensitivity, specificity, PPV and NPV of 92, 100 , 100 and 82% was found. Conclusions: The Pyloriset(R) IgG is a simple and accurate method for detecting H. pylori infection in dyspeptic Du tch patients. The performance of this assay is improved by lowering th e cut-off value (test becomes predominantly more sensitive) and exclud ing older patients (test becomes predominantly more specific). Therefo re serology might eventually replace endoscopy or breath tests in the detection of H. pylori infection, especially in the younger age groups .