Rapid urease test(RUT) is one of the invasive methods for detection of H. pylori infection. H. pylori in the biopsy specimen splits the urea to ammonia in the test container. Elevation of pH by ammonium hydroxide are detected as color change of pH indicator. The advantage of RUT are low-priced, easy-to-use, and rapid time to diagnosis. The disadvantage of RUT are necessity of endoscopy performance and occurrence of false negative. RUT is useful for diagnosis of H. pylori infection before and after eradication treatment. However, the sensitivity of RUT is comparatively low within 6 months after completion of eradication.