CURRENT OR RECENT PROTON PUMP INHIBITOR THERAPY MARKEDLY IMPAIRS THE ACCURACY OF THE [C-14]UREA BREATH TEST

Background There are increasing indications for assessing Helicobacter pylori status by non-invasive means in dyspeptic patients, There is a lso increasing use: of proton pump inhibitor therapy for dyspeptic dis ease. Aims To determine the effect of proton pump inhibitor therapy on the accuracy of the [C-14]urea breath test, Patients [C-14]Urea breat h tests were performed in 20 H. pylori-positive and 13 H. pylori-negat ive dyspeptic patients before commencing omeprazole and after 4 weeks of treatment with 40 mg/day and then 6 months of treatment with 20 mg/ day, Further studies were done in Hi pylori-positive patients to exami ne the time course of the onset and resolution of the effect observed, Results False negative results occurred in 45% of the ii. pylori-posi tive subjects after 4 weeks of omeprazole 40 mg/day and in 28% after 6 months of 20 mg/day, False positive results occurred in 15% of the H. pylori-negative subjects after 4 weeks of omeprazole 40 mg/day, In th e ii. pylori-positive subjects time course studies showed increasing s uppression of the breath test result over the first 2-4 weeks of treat ment, It took a similar time for the breath test result to recover aft er stopping treatment. There was no significant change in H. pylori Ig G serology in the H. pylori-positive patients after 7 months of omepra zole treatment, Conclusions Proton pump inhibitor therapy markedly imp airs the accuracy of the [C-14]urea breath test and, in particular, pr oduces a high proportion of false negative results, The effect is dose related and may persist for 2-4 weeks after stopping therapy. Patient s should be carefully questioned about recent proton pump inhibitor th erapy before accepting a negative breath test result as reliable. Eur J Gastroenterol Hepatol 10:759-764 (C) 1998 Lippincott Williams & Wilk ins.