Comparison of three urease tests for detection of Helicobacter pylori in gastric biopsy specimens

To propose two modified urease tests for the detection of Helicobacter pylori in gastric biopsy specimens. The presence of H. pylori infection was determined in 237 patients undergoing upper gastrointestinal endoscopy. Three media were used for the urease tests: Christensen's 2% urea broth and two urea agar media, modified by increasing the concentration of urea (to 4% and 10%) and phenol red and omitting the nutrients. The modified tests had good sensitivity (> 78%), specificity (96%) and accuracy (> or = 86%) at 2 h using small amounts (15%) of biopsy homogenates. They were statistically more sensitive and accurate than Christensen's broth. Both the modified 4% and 10% urea agar tests are simple, sensitive and specific and can be performed with small amounts of sample.