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

Summary Aim To assess the intra-individual variability of the 13C-octanoic acid breath test using non-dispersive infrared spectrometry for gastric emptying of solids in healthy children. Methods A 13C-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 13C-octanoic acid-labelled pancake and at 15-min intervals for the following 240 min. Breath samples were analysed using non-dispersive infrared spectrometry; 13C-recovery was used to calculate values for gastric half-emptying time (t1/2), gastric lag phase (tlag) and gastric emptying coefficient. Intra-individual variability of the parameters t1/2, tlag and gastric emptying coefficient were expressed as coefficient of intrasubject variation. Results The mean coefficient of intrasubject variation of t1/2 was 13.3 ± 7.9% (range 2.5–29.6%; interindividual range 99–204 min; intra-individual range 5–84 min for t1/2). The mean coefficient of intrasubject variation of tlag was 13.6 ± 7.5% (range 0.8–27.8%) (interindividual range 65–146 min; intra-individual range 1–50 min for tlag). 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 t1/2, tlag and gastric emptying coefficient were independent of the values of t1/2, tlag 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.