Validation of an in-house made rapid urease test kit against the commercial CLO-test in detecting Helicobacter pylori infection in the patients with gastric disorders

BACKGROUND H. pylori is a urease positive organism, and this activity in a gastric biopsy could be considered as a proof of the presence of H. pylori. For the reasons of high price and difficult accessibility to the commercial CLO-test in Iran, we designed an affordable equivalent test with high specificity, accuracy and availability. METHODS Biopsy samples from 80 symptomatic patients with gastrointestinal problems were included in this study. The results of our in-house made rapid urease kit were compared with the commercial CLO-test up to 3 hours and 24 hours after inoculation of the biopsy samples. Culture results and gram staining were proposed as gold standard. RESULTS Helicobacter pylori was isolated from 36 patients (45.0%) after cultivation of biopsy samples. After 3 hours, 33 (91.6%) cases of positive samples for H. pylori, showed urease positive reaction using both, in-house made and CLO-test kits. However, 2 (5.5%) cases showed urease reaction at 24 hours using both the kits. The specificity of 100% was determined for both, in-house made and commercial CLO-test kits after 3 hours. The sensitivity for both the kits was estimated at 97.1% after 3hours. However, after 24 hours, sensitivity and specificity of 97.1% and 88.64% was estimated for the in-house and 97.2 % and 95.4% for the commercial CLO-test kits, respectively. CONCLUSION Specificity and sensitivity of 100% and 97.1 % for up to 3 hours follow biopsy sampling, could be considered as an advantage for our in-house rapid urease kit. Moreover, the rapid urease agar media designed in our lab is cost-effective with adequate sensitivity and specificity levels for the detection of H. pylori, compared with the commercial CLO-test.