Intragastric acidification reduces the occurrence of false-negative urea breath test results in patients taking a proton pump inhibitor

OBJECTIVE: The aim of this study was to investigate whether reducing intrag astric pH, at the time of urea ingestion, decreases the likelihood of false -negative (FN) urea breath test (UBT) results in patients taking a proton p ump inhibitor (PPI). METHODS: Patients with active Helicobacter pylori infection underwent a bas eline C-14-UBT (UBT-1) followed by treatment with lansoprazole 30 mg/day fo r 14 to 16 days. On day 13, patients returned for a repeat standard UBT (UB T-2). Between days 14 to 16, patients underwent a modified UBT (UBT-3), whi ch included consuming 200 ml of 0.1 N citrate solution 30 min before and at the time of C-14-urea administration. Breath samples were collected 10 and 15 min after C-14-urea ingestion. Mean (CO2)-C-14 excretion and the number of FN and equivocal UBT results were compared for the three UBTs. RESULTS: A total of 20 patients completed the study. Lansoprazole caused a significant decrease in mean breath (CO2)-C-14 excretion (disintegrations p er minute) between UBT-1 (2.96 +/- 0.23) and UBT-2 (2.08 +/- 0.52, p < 0.05 ). Lansoprazole caused six (30%) FN and eight (40%) equivocal UBT-2 results . Mean breath (CO2)-C-14 excretion for UBT-3 (677 +/- 514) was greater than for UBT-2 (234 +/- 327, p = 0.001). UBT-3 caused only two (10%) FN and thr ee (15%) equivocal results. The 15-min breath sample caused fewer FN and eq uivocal results than the 10-min sample for both UBT-2 and UBT-3. CONCLUSIONS: Giving citrate before and at the time of C-14-urea administrat ion increases mean breath (CO2)-C-14 excretion and decreases FN and equivoc al UBT results in patients taking a PPI. These observations suggest that it may be possible to design a UBT protocol that will remain accurate in the face of PPI therapy. (Am J Gastroenterol 2001;96: 1028-1032. (C) 2001 by Am . Coll. of Gastroenterology).