Refinement of the 14C-urea breath test for detection of Helicobacter pylori.

BACKGROUND

Helicobacter pylori is recognized as the main etiological factor for chronic gastritis, peptic ulcer and possibly also gastric malignancies. A 14C-urea breath test was successively refined to correctly diagnose the presence of H. pylori.

METHODS

After intake of a 14C-urea cocktail, 14CO2 in breath was trapped in benzethoniumhydroxide/ethanol. Serology by ELISA, followed by Western blot, was used as reference method for confirmation of presence or absence of H. pylori.

RESULTS

Breath measurements at 10 and 20 min were determined to be optimal for diagnostic purposes. With 2.5 microCi of 14C-urea, a sensitivity of 86% and specificity of 100% was obtained for the 10-min values. Corresponding data for the 20-min values were 86% and 99%, respectively. When 50 mmol L(-1) citric acid was added to the 2.5 microCi 14C-urea cocktail, separation between positive and negative results became more distinct along with improved sensitivity of 91% and specificity of 100%. As the isotope amount was reduced to 1.0 microCi in the citric acid-containing cocktail, a sensitivity of 93% and specificity of 100% were obtained at both 10 and 20 min.

CONCLUSION

Diagnostic urea breath test has a high concordance with H. pylori serology, combining ELISA and Western blot. Stepwise refinements proved the optimal urea breath test cocktail to include 1.0 microCi 14C-urea in citric acid solution with breath measurement at 10 min.