Conventional 13C-urea breath testing (13C-UBT) includes a test meal to delay gastric emptying, which, theoretically, improves the accuracy of the test. Citric acid has been proposed as the best test meal. However, recent studies have suggested that a test meal may not be necessary.


To investigate a new 13C-UBT protocol without a test meal in a Chinese population.


Consecutive dyspeptic patients referred for upper endoscopy were recruited. 13C-UBT was performed on two separate days with or without a test meal (2.4 Gm citric acid) and compared with the ‘gold standard’ (CLO test and histology).


Two hundred and two patients were tested. Using receiver operating characteristics (ROC) analysis, the optimal delta-value and optimal measurement interval for UBT were 5% and 30 min, respectively, both with or without a test meal. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of 13C-UBT with citric acid (96.5%, 97.7%, 98.2%, 95.6%, 97.0%) were similar to 13C-UBT without a test meal (94.7%, 97.7%, 98.2%, 93.5%, 96.0%).


This simplified 13C-UBT protocol without a test meal produced highly accurate and reliable results in the Chinese population.