Usefulness of the l ‐type Wako Helicobacter pylori antibody J test

Background and aim Helicobacter pylori antibody levels in the blood are currently measured using an ELISA. In April 2016, FUJIFILM Wako Pure Chemical Corporation launched the "l-type Wako Helicobacter pylori antibody J" test, which is based on the latex agglutination turbidimetric immunoassay. In this study, we investigated the usefulness of the Wako test. Methods We measured H. pylori antibody levels using both the ELISA and Wako test in 180 patients who underwent upper gastrointestinal endoscopy at our hospital between September 2017 and February 2019. Ninety patients were infected with H. pylori. We calculated the diagnostic accuracy, sensitivity, and specificity of each test and the concordance rate between the ELISA and Wako test. If lower limits of 90% confidence intervals (CIs) for each diagnostic validity exceeded the 85% threshold, the usefulness of the diagnostic test was confirmed. Results The diagnostic accuracy, sensitivity, and specificity were 94.4% (90% CI, 90.8-97.0%), 94.4% (90% CI, 88.7-97.8%), and 94.4% (90% CI, 88.7-97.8%), respectively, when the Wako test was used, and 94.4% (90% CI, 90.8-97.0%), 88.9% (90% CI, 81.9-93.8%), and 100% (90% CI, 96.0-100%), respectively, when the ELISA was used. The concordance rate between the two tests was high (κ = 0.8444). Conclusions We confirmed the usefulness of the Wako test, especially when screening for H. pylori infection, due to its high sensitivity.