Variability of the 13C-acetate breath test for gastric emptying of liquids in healthy children.

Purpose: Scintigraphy is considered as the "gold standard" for measuring gastric emptying (GE). The 13 C-acetate breath test ( 13 C-ABT) offers an attractive alternative to measure GE of liquids as it is nonradioactive. The aim of this study was to assess the variability of the 13 C-ABT for GE of liquids in healthy children using nondispersive infrared spectrometry (NDIRS). Methods: The 13 C-ABT was repeated at least 2 times in 21 healthy children (6 girls and 15 boys), aged between 6.2 and 16.4 years, 2 to 7 days apart. After an overnight fast, a standardized milk drink, labeled with 50 or 100 mg 13 C-acetate according to weight, was administered. Breath samples were taken before feeding, at 5-minute intervals for the first 40 minutes and at 10-minute intervals for the following 140 minutes after feeding. Breath samples were analyzed 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). Intraindividual variabilities of the parameters t 1/2 , t lag , and GEC were expressed as coefficient of intrasubject variation (CV). Results: The median CV of t 1/2 was 8.3% (CV range, 1.6%-16.2%; t 1/2 interindividual range, 65-112 minutes: and t 1/2 intraindividual range, 4-33 minutes). The median CV of f lag was 16.6% (CV range, 2.0%-26.6%; t lag interindividual range, 31-76 minutes; and t lag intraindividual range, 1-35 minutes). The median CV of GEC was 4.3% (CV range, 0.8%-15.7%; GEC interindividual range. 3.81-4.89; GEC intraindividual range, 0.08-1.31). The CVs of t 1/2 , t lag , and GEC were independent of age, sex, weight, height, and measured values of t 1/2 , t lag , and GEC. Conclusions: The 13 C-ABT using NDIRS is an easy, non-invasive, and nonradioactive procedure with a large intraindividual variation for measuring GE of liquids in healthy children, but comparable to the variation reported with other techniques.