Abstract: A PRELIMINARY INVESTIGATION OF ~(13)C BACKGROUND IN ~(13)C-UREA BREATH TESTHu Yufang; Li Xiaoming; Jiang Ji; Yue Xiangping; Wang Shizhen(Peking Union Medical College Hosptal, Beijing)Abstract:During the 13C-urea breath test which is used for diagnosis of the helicobacter pyloric infection(HP), the 13C background values are measured in 495 normal donors in Beijing, Shandong, Jiangyuand Guizhou. The fluctuation is less than 0. 2% for these areas and is about 0. 1% within the samearea. Through replacing of the individual 13C background values by the averaged values from localareas, the coincident rate for diagnosis of HP is higher than 98%.Keywords: 13C-urea breath test background