Variability of the 13C‐Acetate Breath Test for Gastric Emptying of Liquids in Healthy Children

Scintigraphy is considered as the “gold standard” for measuring gastric emptying (GE). The 13C‐acetate breath test (13C‐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 13C‐ABT for GE of liquids in healthy children using nondispersive infrared spectrometry (NDIRS). The 13C‐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 13C‐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 13C recovery was used to calculate values for gastric half‐emptying time (t1/2), time of peak 13C exhalation, or gastric lag phase (tlag) and gastric emptying coefficient (GEC). Intraindividual variabilities of the parameters t1/2, tlag, and GEC were expressed as coefficient of intrasubject variation (CV). The median CV of t1/2was 8.3% (CV range, 1.6%‐16.2%; t1/2interindividual range, 65‐112 minutes; and t1/2intraindividual range, 4‐33 minutes). The median CV of tlagwas 16.6% (CV range, 2.0%‐26.6%; tlaginterindividual range, 31‐76 minutes; and tlagintraindividual 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 t1/2, tlag, and GEC were independent of age, sex, weight, height, and measured values of t1/2, tlag, and GEC. The 13C‐ABT using NDIRS is an easy, noninvasive, 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.