Serologic screening before endoscopy: The value of Helicobacter pylori serology, serum recognition of the CagA and VacA proteins, and serum pepsinogen I

Background: We wanted to assess the diagnostic value of prc-endoscopy scree ning by Helicobacter pylori serology, serum recognition of the CagA and Vac A proteins, and serum pepsinogen I levels (sPGI) in patients up to 55 years of age with uncomplicated simple dyspepsia. Methods: Consecutive dyspeptic patients referred for open-access endoscopy, excluding patients with alarm symptoms, recent intake of acid suppressants, or ingestion of non-steroida l anti-inflammatory drugs. H. pylori status was determined by histology and urease testing. H. pylori serologic status was determined with the enzyme- linked immunosorbent assay (ELISA) and Western blotting, serum recognition of CagA and VacA with Western blot, and sPGI levels by radioimmunoassay. Re sults: One hundred and fifteen patients were studied (mean age, 40 years; r ange, 20-55 years), of whom 58 were H. pylori-positive in biopsy-based test s. Twenty-one patients (18%) had significant gastroduodenal lesions (erosio ns, ulcers, or cancer). The sensitivity (specificity) of the ELISA (optimiz ed) and Western blot in determining H. pylori status was 94.8% (89.5%) and 100% (96.4%), respectively. Screening strategies based on the ELISA or West ern blot for determining H. pylori serologic status would have detected 95% or 100% of significant lesions, respectively, and each 'saved' 47% of endo scopies for simple dyspepsia. Serum recognition of the CagA protein would h ave detected 95% of significant lesions and 'saved' 55% of endoscopies, whe reas recognition of the VacA protein would have detected only 81% of the le sions. Screening by H. pylori serology plus a 'low' (<55 ng/ml) or 'high' s PGI (>125 ng/ml) would detect only 57% of significant lesions, although the only case of cancer was included in the hypopepsinogenaemic subgroup of ju st 11 patients. Conclusions: In patients with uncomplicated, simple dyspeps ia up to 55 years of age, screening by H. pylori serology identified 95%-10 0% of patients with significant gastroduodenal lesions while potentially sa ving 46.9% of endoscopies. Serum recognition of the CagA protein identified 95% of lesions and would have saved an additional number of endoscopies (7 .9%) compared with basic serology. Measurement of sPGI was of limited diagn ostic value.