[The diagnostic accuracy of gastric urease activity for Helicobacter pylori]

The diagnostic accuracy of gastric urease activity for Helicobacter pylori (HP) infection were studied in 98 patients with peptic ulcer, gastritis and chronic renal failure. Gastric aspirates were analyzed for urea nitrogen and ammonia. Urease activity was calculated as the ratio of gastric ammonia to sum of gastric urea nitrogen and ammonia. Gold standard assessments to HP infection were rapid urease test, histology and/or culture. The results showed that the values of urease activity in patients with HP infection higher than that in patients without HP infection. This were further assessed by eradication of HP. Sixteen patients with HP infection were treated with DeNol 330 mg/day for 4 weeks. HP was eradicated in 8/16 patients. In those cases urease activity reduced (P < 0.05). If taken 0.31 as the cut-off index of urease activity to diagnosis HP infection, the sensitivity, specificity and accuracy were 95%, 84%, 93% respectively and were not affected by blood urea nitrogen.