Validity of 13C octanoic acid breath test for measurement of solid meal gastric emptying time in children

Abstract

Background/Purpose It is important to establish a physiologic range of gastric emptying (GE) in children. Gastric emptying time measured with 99Tc-labeled solid meal (GE Tc) is the gold standard. Large-scale studies with GE Tc are ideal but not feasible because of radiation exposure. The 13C-labeled octanoic acid breath test (GE 13C) does not involve radiation and is suitable for large studies. The aim of this study was to validate GE 13C with GE Tc and to explore whether GE 13C could be used to establish a physiologic range of GE in children. Method Twenty-five healthy children underwent simultaneous GE Tc and GE 13C using a standardized solid test meal. The time taken for the stomach to empty half its content (T½ 13C) and solid lag phase (lag 13C) for GE 13C were computed from the fractional excretion of 13C in expired air. T½ 13C and lag 13C were compared with corresponding values obtained by GE Tc. Result Correlation coefficient between T½ 13C and T½ Tc was 0.69 ( P < .01; r = 0.92 if 3 outliers were omitted). Correlation coefficient between lag 13C and lag Tc was 0.39 ( P < .05). There was good agreement between the methods by the Bland Altman method. Conclusion There is good agreement between GE 13C and GE Tc. GE 13C can be safely used to establish the reference range of GE in healthy children.