EFFECT OF SIMETHICONE ON THE ACCURACY OF THE RAPID UREASE TEST

Objective Simethicone, which is a principal ingredient in the defoamin g agent used during gastroscopy, can inhibit the growth of Helicobacte r pylori (MIC, 64-128 mg/l). This prospective study was designed to ev aluate the in vivo and in vitro effects of simethicone on the accuracy of the rapid urease test (RUT),Methods In the in vivo study, three se ts of gastric biopsies (two from the antrum, and one from the corpus) were taken from 75 patients, The first set was examined histologically , and the second set was used for the RUT (pre-simethicone RUT), Then, 25 ml simethicone (1200 mg/l) was introduced into the stomach for a c ontact time of 1 min, A third set of gastric biopsies was taken for th e RUT (post-simethicone RUT), In the in vitro clinical study, 41 patie nts were recruited, The first set of gastric biopsies was used for the RUT (pre-incubation RUT), The second set was incubated in 1 mi of sim ethicone for 5 min before being used for the RUT (post-incubation RUT) . In the spectrophotometric study, urease activity before and after in cubation in simethicone for 5 min was quantified in 12 patients by mea suring the absorbance at 560 nm. Results Reading at 15 min, the concor dance rate between the pre-simethicone and post-simethicone RUT was 98 %. In the in vitro clinical study, the concordance rate between the pr e-incubation and post-incubation RUT was 97%. The spectophotometric st udy showed a significant reduction of 43% in urease activity after inc ubation in simethicone. Conclusion The application of a defoaming agen t containing simethicone does not affect the accuracy of the RUT, Howe ver, simethicone modestly suppresses urea hydrolysis, Eur J Gastroente rol Hepatol 10:851-854 (C) 1998 Lippincott Williams & Wilkins.