Simplified 13C-urea breath test with a new infrared spectrometer for diagnosis of Helicobacter pylori infection

Background and Aim: Infrared spectrometry has correlated excellently with mass spectrometry in detecting the ratio of (CO2)-C-13 to (CO2)-C-12 in breath samples. The present study aimed to evaluate the accuracy of the C-13-urea breath test (C-13-UBT) using a new model of infrared analyzer. Methods: A total of 600 patients who were undergoing upper endoscopy without receiving eradication therapy were entered into the study. Culture, histology, and rapid urease test on biopsies from the antrum and corpus of the stomach were used for the determination of Helicobacter pylori infection. Breath samples were collected before and 20 min after drinking 100 mg C-13-urea in 100 mL water. The optimal cutoff value was determined by the receiver operating characteristic curve. Results: Of the 586 patients who were eligible for analysis, 369 were positive for H. pylori infection, 185 were negative for H. pylori infection, and 32 were indeterminate. When the appropriate cutoff value was set at 3.5parts per thousand, a sensitivity of 97.8%, a specificity of 96.8% and an accuracy of 97.5% were obtained using the C-13-UBT. The accuracy of the C-13-UBT decreased when CO2 concentration in the breath sample was < 2%, as compared with >= 2% (93.6% vs 97.7%), mainly because of a decrease in specificity (81.8% vs 97.7%). There were 2.7% of patients with Delta(CO2)-C-13 values that fell between 3.0-4.5 parts per thousand, in whom the risk of error was 47%. Conclusions: The C-13-UBT performed with infrared spectrometry is a highly sensitive, specific, and non-invasive method for the detection of H. pylori infection. The immediate availability of the test result and technical simplicity make it particularly effective in routine clinical practice. (C) 2003 Blackwell Publishing Asia Pty Ltd.