13C-Spirulina Gastric Emptying Breath Test Normative Values in Healthy Children- A Multicenter Study with Comparison to Symptomatic Children.

BACKGROUND Diagnosing pediatric gastroparesis presents a significant challenge due to lack of normative data in children. We aimed to determine normative values for gastric emptying using the non-radioactive 13C-Spirulina gastric emptying breath test (13C-GEBT) in a large cohort of healthy children (HC) and examine differences compared to children with gastroparesis-like symptoms (GLS). METHODS 301 HC ages 7-18 years completed the 13C-GEBT with 10 different breath samples x 4 hours. 13CO2 excretion rate (kPCD) was determined by change in 13CO2/12CO2. Outcome variables included: kPCD at 10 time points, peak (maximum) kPCD, time to peak (Tmax) kPCD, and area under curve (AUC) of 13CO2 excretion, along with breath test half emptying time (BT t ½). Results were compared to 13C-GEBT data from peri- and post-pubertal patients 11-18 years of age with GLS. RESULTS 216 HC, 51·4% female, completed the test meal within the allotted time. Females vs. males had lower peak kPCD (p=0·003), longer Tmax (p=0·04), lower AUC (p<0·001), and longer BT_t½ (p<0·0001). Peak kPCD (p=0·01, p<0·001) and AUC (p=0·012, p<0·001) were higher in pre- vs peri- and post-pubertal children. BT_t½ and Tmax were shorter in HC vs. GLS (p<0·001, p<0·0001, respectively), consistent with faster gastric emptying in HC. Normative reference values based on 5th percentile kPCD and Tmax were established for peri- and post-pubertal females. An algorithm incorporating key variables demonstrated 80.8% sensitivity for diagnosis of gastroparesis. CONCLUSIONS This study demonstrates sex and pubertal differences in gastric emptying in children and provides the first reference values for female children.