The British Society of Gastroenterologists suggests that dyspeptic patients under 45 years of age should be screened serologically for Helicobacter pylori infection, to reduce endoscopy workload. We have compared the sensitivity, specificity, and predictive value of six commercial serological kits intended for pre-endoscopy screening for H. pylori with histopathology and culture in 82 dyspeptic patients, 35 of whom were H. pylori positive. The kits' sensitivities were as follows: Bio-Rad GAP 100%, Helico-G 100%, Premier 97%, and Pyloriset EIA-G 94%. Poor specificity of the ELISA kits--Bio-Rad GAP 67%, Helico-G 67%, Premier 85%, and Pyloriset EIA-G 76%--was due to previous treated or cleared H. pylori infection. Allowing for previously documented H. pylori infection or peptic ulcer improved specificity--Bio-Rad GAP 84%, Helico-G 84%, Premier 100%, and Pyloriset EIA-G 90%. The Pyloriset Dry latex kit had a higher specificity (86%) but a lower sensitivity (75%) than the Oxoid latex kit (specificity 70%, sensitivity 94%). The qualitative Premier Launch kit had the best overall results (and was the easiest ELISA to perform). Reliable serological diagnosis of H. pylori is now suitable for screening dyspeptic patients.