The characteristics of oxygen concentration and the role of correction factor in real-time GI Breath Test
ABSTRACTA high quality end-expiratory breath sample is required for a reliable GI breath test result. Oxygen (O2) concentration in the breath sample can be used as a quality marker. This study investigated the characteristics of oxygen concentration in breath sample and the issues with using a correction factor in real-time breath test. The results indicated 95.4% of 564 patients were able to achieve an O2 concentration below 14% in their end-expiratory breath. A further 228 samples were studied and revealed that the distribution of O2 concentration was between 16.5% and 9.5%. Applying a correction factor to predict the end-expiratory H2 and CH4 values led to an error of −28.0% and −15.2% respectively. The correction factor algorithm based on limiting O2 at 14% has resulted in a false negative diagnosis in one case. This study has also indicated the continuous O2 measurement is essential to ensure breath sample quality by preventing secondary breathing during real-time breath collection.