Detection of Helicobacter pylori antibodies in a pediatric population: comparison of three commercially available serological tests and one in-house enzyme immunoassay

Abstract

A serum immunoglobulin G enzyme immunoassay (EIA) for Helicobacter pylori antibodies already in use in adults was evaluated with 99 pediatric serum samples to determine its usefulness for the study of H. pylori disease in children. The reference method used was either the (13)C-urea breath test or a biopsy culture of gastric mucosa. In children, an EIA cutoff of 0.35 absorbancy unit yielded sensitivity, specificity, and positive and negative predictive values of 93, 97, 93, and 97%, respectively. The cutoff recommended when this EIA was published for use in adults was 0.70 absorbancy unit (H. Gnarpe, P. Unge, C. Blomqvist, and S. Mäkitalo, APMIS 96:128-132, 1988). Another subset of 169 serum samples taken from children was analyzed by four serological tests in order to compare the performance of the in-house EIA with the Pyloriset, HM-CAP, and Helico-G kits. For the 169 samples, 10 (5.9%) false-positives and no false-negatives occurred with the Helico-G, 3 (1.8%) false-positives and no false-negatives occurred with the Pyloriset, and 3 (1.8%) false-positives and 1 (0.6%) false-negative occurred with the HM-CAP. For the 169 samples, 1 (0.6%) false-positive and no false-negatives occurred with the in-house EIA. Serological detection of H. pylori antibodies with our EIA seems to be valuable in diagnosing H. pylori infection in children, but only if a lowered, specific pediatric cutoff is established. The commercial kits, particularly the Helico-G, seem to overdiagnose pediatric H. pylori infection. A positive serological test for H. pylori infection, particularly for children, needs to be confirmed by a reference method because of the possibility of spontaneous eradication of infection, with a lingering serological response.