A Combination Of Serum Anti-Helicobacter Pylori Antibody Titer And Kyoto Classification Score Could Provide A More Accurate Diagnosis Of H Pylori

Background We previously showed that the endoscopic Kyoto classification for gastritis could predict Helicobacter pylori infection in individuals with a high negative titer of serum anti-H pylori antibodies. This study evaluated H pylori infection and the Kyoto classification score in patients with a low negative titer (<3 U/ml), high negative titer (3-9.9 U/ml), low positive titer (10-49.9 U/ml), and high positive titer (>= 50 U/ml). Methods Serum antibody levels, Kyoto classification score and histology were investigated in 870 individuals with no history of H pylori-eradication therapy. Urea breath tests (UBTs) were additionally conducted for patients with a low negative titer and a Kyoto score >= 1 or an antibody titer >= 10 U/ml and a Kyoto score of 0 or 1. UBTs and/or histological studies were conducted for participants with a high negative titer. Results False diagnoses based on anti-H pylori antibody titers were observed in 0.3% of the low-negative-titer group, 11.7% of the high-negative-titer group, 18.9% of the low-positive-titer group and 2.2% of the high-positive-titer group. Surprisingly, false diagnoses based on antibody titers were noted in 63.2% of patients with a low positive titer and a Kyoto score of 0 and in 62.5% of patients with a high negative titer and a Kyoto score >= 2, respectively. Conclusions Endoscopic findings could predict false diagnoses determined using serum antibody titers.