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 intragastric pH, at the time of urea ingestion, decreases the likelihood of false-negative (FN) urea breath test (UBT) results in patients taking a proton pump inhibitor (PPI).

Methods: Patients with active Helicobacter pylori infection underwent a baseline 14C-UBT (UBT-1) followed by treatment with lansoprazole 30 mg/day for 14 to 16 days. On day 13, patients returned for a repeat standard UBT (UBT-2). Between days 14 to 16, patients underwent a modified UBT (UBT-3), which included consuming 200 ml of 0.1 N citrate solution 30 min before and at the time of 14C-urea administration. Breath samples were collected 10 and 15 min after 14C-urea ingestion. Mean 14CO2 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 14CO2 excretion (disintegrations per 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 14CO2 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 three (15%) equivocal results. The 15-min breath sample caused fewer FN and equivocal results than the 10-min sample for both UBT-2 and UBT-3.

Conclusions: Giving citrate before and at the time of 14C-urea administration increases mean breath 14CO2 excretion and decreases FN and equivocal 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.