Comparison of rapid serological tests (FlexSure HP and QuickVue) with conventional ELISA for detection of Helicobacter pylori infection.

BACKGROUND

There is a need for accurate and rapid tests for Helicobacter pylori infection especially since the recent National Institutes of Health Consensus Development Conference on H. pylori in peptic ulcer disease charged the medical community with treating H. pylori infection in all patients with H. pylori and ulcer disease.

METHODS

We prospectively compared a simple, rapid serological test (FlexSure HP, SmithKline Diagnostics) for the detection of serum IgG antibodies against H. pylori with another rapid test (QuickVue, Quidel) and two enzyme immunoassays (HM-CAP, Enteric Products, and PyloriStat, BioWhittaker). Serum samples from 551 individuals including both symptomatic patients (196) and asymptomatic volunteers (355) were tested for the presence of IgG antibodies against H. pylori. The presence or absence of active H. pylori infections was determined using the [13C]-urea breath test.

RESULTS

All of the serological tests performed well. FlexSure HP had calculated sensitivity, specificity, and accuracy of 94.4, 87.6, and 91.1%, respectively, relative to the urea breath test. In 49 of the 551 samples, the urea breath test and FlexSure HP did not agree. Those samples were tested with HM-CAP immunoassay to confirm presence or absence of IgG antibodies against H. pylori. After the resolution of the discordant results, the sensitivity, specificity, and accuracy of FlexSure HP were 96.0, 95.1, and 95.6%, respectively, and were comparable to HM-CAP and PyloriStat. FlexSure HP was compared with histology or culture in 75 cases, and the accuracy was 100%. FlexSure HP and QuickVue were compared using 200 serum samples. FlexSure HP was more specific (88.7 vs 79.4%) and accurate (91 vs 84%) than QuickVue (p < 0.05 for both), relative to the urea breath test with discordant samples unresolved. FlexSure HP was also simpler to use, easier to interpret, and faster than QuickVue. FlexSure HP required no sample dilution, one reagent, four steps, and 5 min to complete.

CONCLUSION

FlexSure HP is an excellent option for in-office tests for the physician who desires immediate results or for small laboratories that do not have the volume of H. pylori testing to justify ELISA test formats.