STOOL ANTIGEN TEST FOR HELICOBACTER PYLORI INFECTION: A META-ANALYSIS OF DIAGNOSTIC TEST ACCURACY

BACKGROUND: Helicobacter pylori affects approximately half of the world's population and is considered a risk factor to several gastrointestinal disorders. In this sense, the stool antigen test (SAT) is a convenient and patient-friendly non-invasive option for detecting H. pylori. However, despite having been previously evaluated, some gaps in its accuracy still remain. Consequently, a thorough statistical synthesis to provide further evidence on the diagnostic accuracy of SATs for the diagnosis of H. pylori infection is required.
AIM: To determine and compare the diagnostic accuracy of conventional and rapid SATs for the diagnosis of H. pylori infection in adult patients.
METHODS: An independent search in PubMed/MEDLINE, Embase and Web of Science electronic databases was conducted through July 25, 2023. We included studies evaluating the accuracy of SATs against a reference standard. Assessment of methodological quality was performed using the QUADAS-2 tool. We utilized the bivariate random-effects model to calculate sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR-), as well as the diagnostic odds ratio (DOR), and their 95% confidence intervals (95% CI). Subgroup analyses were conducted based on model and assessment technique. To investigate a possible threshold effect, we conducted Spearman correlation analysis, and generated summary receiver operating characteristic (SROC) curves to assess heterogeneity. Finally, we visually inspected a funnel plot and used Egger’s test to evaluate publication bias.
RESULTS: Titles and abstracts of 5,463 studies were screened; 89 articles were retrieved and selected for full-text reading. Finally, 60 studies were included in the diagnostic test accuracy meta-analysis. Conventional SAT demonstrated superior diagnostic accuracy, with higher sensitivity (92.19% vs. 85.79%), specificity (92.93% vs. 91.18%), likelihood ratios (LR+ 9.68 vs. 8.16; LR- 0.10 vs. 0.15), and AUC (0.958 vs. 0.940) compared to rapid SAT. Notably, the DOR for conventional SAT (114.70) significantly outperformed rapid SAT (DOR 57.72), making it the preferred tool for the diagnosis of H. pylori infection. Correlation analysis revealed no threshold effect (Conventional SAT r = 0.23; Rapid SAT r = -0.19), and SROC curves showed consistent accuracy. Both conventional and rapid stool antigen tests showed excellent accuracy, with AUC values near 1.00, which demonstrates that both are adequate diagnostic tools in clinical practice.
CONCLUSION: Our study establishes evidence of the superior diagnostic accuracy of conventional stool antigen tests over rapid SATs for detecting Helicobacter pylori infection in adults. Also, we provide valuable insights into the impact of using monoclonal or polyclonal antibodies and different assessment techniques on diagnostic accuracy measures.