DIAGNOSIS OF HELICOBACTER-PYLORI INFECTION IN A DEVELOPING-COUNTRY - COMPARISON OF 2 ELISAS AND A SEROPREVALENCE STUDY

Serology to detect antibodies to Helicobacter pylori is not frequently used as a diagnostic tool in developing countries. When compared to a commercial ELISA, an ELISA constructed and validated in Thailand had a higher sensitivity (98% vs. 85%), specificity (76% vs. 66%), and neg ative predictive value (97% vs. 76%) for the detection of H. pylori in fection among 104 patients with dyspepsia evaluated by endoscopy. The positive predictive value was 88% for both tests. Serum antibody level s fell significantly 5-8 months after eradication of infection in 8 Th ai patients (P = .009). By 8 years of age, >50% of Thai persons living in urban and rural locations were seropositive. The low negative pred ictive value of the commercial ELISA limits the usefulness of this ass ay as a diagnostic tool in Thailand and suggests a need to reevaluate H. pylori serologic tests when used in populations living in developin g countries.