Clinical implication of immunoglobulin G levels in the management of patients with Helicobacter pylori infection.

Abstract

OBJECTIVE: The objective of this research was to gauge the diagnostic utility of serology tests compared with urea breaths tests (UBTs) and determine reliable threshold values/ranges for diagnosis of Helicobacter pylori infection using only immunoglobulin (Ig) G results. METHODS: Data were obtained from 371 patients with UBTs and/or serology tests. Quantitative results were converted to multiple of minimum positive value (MMPV). Results were paralleled to obtain percentage change in serum IgG levels and 95% confidence intervals were obtained to establish new ranges for diagnosis. RESULTS: Treated patients with only serology tests in a time frame of 3 to 6 months after final treatment displayed a 68.33% ± 2.95% decrease in 95% confidence interval of serum IgG. Uninfected patients with serology and UBT results within 2 weeks displayed a range of 1.32 ± 0.23 MMPV; infected patients produced a range of 3.32 ± 0.88 MMPV. CONCLUSION: Treated patients should display a 65.38% to 71.28% decrease in serum IgG levels, along with an ending IgG level of ≤1.75 U/mL or ≤4.025 EV (ELISA value). Before treatment or exposure, patients with serum IgG values of 1.09 to 1.55 U/mL or 2.507 to 3.565 EV or lower are generally uninfected. Because of the lower cost and high confidence of results, we believe that IgG testing should be considered as a reasonable and even perhaps preferred method of monitoring H. pylori infections.