Evaluation of a new immunochromatographic test for Helicobacter pylori IgGantibodies in elderly symptomatic patients

Aim: To determine the diagnostic value of a new serum and whole blood serol ogical IgG antibody test, FlexPack HP, for the diagnosis of Helicobacter py lori in elderly symptomatic patients. Methods: 94 consecutive symptomatic patients who underwent upper endoscopy were studied (mean age, 62.6 years). On endoscopy, the presence of H. pylor i infection was examined by biopsies from gastric antrum and body for rapid urease test and histologic examination. Blood was drawn prior to endoscopy and both blood and serum were immediately analyzed for human IgG antibodie s to H. pylori by a new commercially available qualitative immunochromatogr aphic method, FlexPack HP. This test incorporates high-molecular weight cel l-associated proteins (HM-CAP), which are highly specific for H. pylori IgG antibodies. Results: Overall agreement for FlexPack HP whole blood vs FlexPack HP serum was 100%, and agreement with biopsy results was 71%. The gold standard (de tection of H. pylori by histology or urease test) identified H. pylori in 6 1 patients (65%). Complete agreement was observed between the gold standard test and the serology kit in 72% (68/94) of sera (51 positive and 17 negat ive). Disagreement was found in sera of 26 patients; 16 sera were negative by the gold standard and positive by FlexPack HP and 10 patients were found negative by serology, The sensitivity of FlexPack HP was 84% and the speci ficity 52% when compared with the gold standard. Conclusions: FlexPack HP serum and whole blood test is a simple and reliabl e method for the detection of H. pylori antibodies, with 100% agreement bet ween the serum and blood results. In the elderly symptomatic patients the s ensitivity of FlexPack HP was similar to that of other serologic tests, but the specificity was relatively low, limiting its use in this population.