REPRODUCIBILITY OF THE 13 C OCTANOIC ACID BREATH TEST FOR GASTRIC EMPTYING OF SOLIDS IN CHILDREN.

Abstract

Introduction: The “gold standard” for measuring gastric emptying (GE) is scintigraphy. The 13 C octanoic acid breath test (13COBT) is an interesting alternative to measure GE of solids, as it is non radioactive. The 13COBT using mass spectrometry has been validated against scintigraphy and has a physiological day-to-day variability in adults as well as in children. There are no data in the literature concerning the use of Non Dispersive InfraRed Spectrometry (NDIRS) in the evaluation of GE of solids with octanoic acid in children. Aim: To assess the reproducibility of the 13COBT for GE of solids in children using NDIRS. Methods: GE for solids was tested in 19 healthy children (6 girls, 13 boys). After an overnight fastening, a solid test meal consisting of a pancake with a caloric content of 230 kcal, and labelled with 50 μl 13 C octanoic acid, was given. Breath samples were taken before feeding and at 15 minutes intervals after feeding for 4 hours. Samples were analysed using NDIRS, and 13 C recovery was used to calculate values for gastric half emptying time (t 1/2), time of peak 13 C exhalation or gastric lag phase (t lag) and gastric emptying coefficient (GEC). The 13COBT was then repeated ≥2 times 2 to 7 days apart. Intra-individual variability and reproducibility of the parameters t 1/2, t lag and GEC were expressed as coefficient of variation (CV). Results: The mean age was 12.83 years (range 6.75-17.08), the median CV of t 1/2 was 12.9% (range 2.5-29.6) for a t 1/2 with a range between 89 and 220 minutes, the median CV of t lag was 12.4% (range 0.8-27.8) for a t lag with a range between 61 and 163 minutes, the median CV of GEC was 10.9% (range 3.4-30.2) for a GEC with a range between 1.8 and 4.2. The median CV of t 1/2, t lag and GEC was independent of the values of t 1/2, t lag and GEC. Conclusions: The 13COBT using NDIRS is a non-radioactive, easy and less expensive procedure for measuring the gastric emptying of solids in children with very good reproducibility.