Relevance of Adjusted Cut-off Values in Commercial Serological Immunoassays for Helicobacter pylori Infection in Children

Abstract

We assessed the sensitivity and specificity of H. pylori IgG and IgA with a commercial immunoassay performed in Chile and a second non-commercial immunoassay performed in a reference laboratory in the United States, in serum of 80 children and adults referred for gastrointestinal endoscopies in a developing country. Overall, 56% of the patients were infected with H. pylori based on rapid urease test and staining techniques on gastric biopsies. When Receiver Operator Curves (ROC) were developed, the sensitivity and specificity were similar for IgG and IgA. Both immunoassays exhibited better specificity, positive and negative predictive value (NPV) in children than in adults when cut-off values were corrected according to the local population than when they were assessed using the cut-off values pre-defined in other populations. These results underline the need to establish more precise cut-off values corrected in the local populations where assessments of antibodies as diagnostic markers of H. pylori infection are planning.

Helicobacter pyloriDetection and Antimicrobial Susceptibility Testing

“…Serology in children younger than 10 years has encountered the problem of a lower antibody titer than in adults, and therefore, a specific cutoff value must be chosen (81,205,511). In addition, laboratory serology may not be well accepted by children because, although it is minimally invasive, the child may refuse the serum sampling.…”

Gastric Cancer is Related to Early Helicobacter pylori Infection in a High-Prevalence Country

“…The corresponding score statistics (P) were 13.95 (0.001), 16.19 (0.001), 16.90 (0.010), and 6.48 (0.011), respectively. For educational level, the score statistic (P) was 5.02 (0.081), suggesting the absence of differences in the degree of H. pylori infection across socioeconomic levels, after controlling for gastric cancer mortality, age, and gender (Table 3).…”

“…Serum positivity on that study was defined on the basis of cutoff values established by the mean + 3 SD of a normal population from the United States. In a recent study, we compared the noncommercial immunoassay with the commercial assay used in the current study and determined a sensitivity of 90% and a specificity of 50% for the adult group (16). Because variation in sensitivity and specificity according to age has been previously reported, we further extended our analysis by including an older population and the best cutoff values were chosen based on receiver operator curves, with a cutoff value of 72.79 arbitrary units/mL for IgG, reaching a sensitivity and specificity of 87.5% and 62%, respectively.…”

Is Helicobacter Pylori Associated with a Migraine?

“…IgG is much more specific in children than adults, affirming the fact that adults are more likely to have been exposed to H. pylori in the past [24,25]. IgM was not implemented for investigation as it has been found to have little diagnostic utility for H. pylori infections and is elevated only acutely after infection, whereas H. pylori infections are generally chronic [26].…”