Variability of the 13C-octanoic acid breath test for gastric emptying of solids in healthy children

Aim To assess the intra-individual variability of the C-13-octanoic acid breath test using non-dispersive infrared spectrometry for gastric emptying of solids in healthy children. Methods A C-13-octanoic acid breath test was performed at least two times in 19 healthy children (age 12.4 +/- 2.7 years) 2-7 days apart to measure gastric emptying of solids. Breath samples were taken before eating a C-13-octanoic acid-labelled pancake and at 15-min intervals for the following 240 min. Breath samples were analysed using non-dispersive infrared spectrometry; C-13-recovery was used to calculate values for gastric half-emptying time (t(1/2)), gastric lag phase (t(lag)) and gastric emptying coefficient. Intra-individual variability of the parameters t(1/2), t(lag) and gastric emptying coefficient were expressed as coefficient of intrasubject variation. Results The mean coefficient of intrasubject variation of t(1/2) was 13.3 +/- 7.9% (range 2.5-29.6%; interindividual range 99-204 min; intra-individual range 5-84 min for t(1/2)). The mean coefficient of intrasubject variation of t(lag) was 13.6 +/- 7.5% (range 0.8-27.8%) (interindividual range 65-146 min; intra-individual range 1-50 min for t(lag)). The mean coefficient of intrasubject variation of gastric emptying coefficient was 12.5 +/- 6.8% (range 3.4-30.2%; interindividual range 2.3-3.9; intra-individual range 0.17-1.4 for gastric emptying coefficient). The coefficient of intrasubject variations of t(1/2), t(lag) and gastric emptying coefficient were independent of the values of t(1/2), t(lag) and gastric emptying coefficient. Conclusions Gastric emptying in healthy children is characterized by a large inter- and intra-individual variability and is concordant with the results obtained with other techniques.