The goal of this clinical trial is to define the normal response to the 13C-Spirulina Gastric Emptying Breath Test (GEBT) in children, so that we can use this test to help diagnose children that are suspected of having a condition called gastroparesis, which means that food doesn't empty from their stomach normally.

Participants will blow into test tubes to collect breath samples before and after eating a scrambled egg GEBT meal that contains a small amount of specially grown Spirulina (a blue-green alga used as a dietary supplement) that contains mostly carbon-13 (a non-radioactive kind of carbon atom). Analysis of the amount of 13C in the carbon dioxide in breath before and after eating the GEBT meal can measure how fast food is emptying from the stomach.

Children will complete questionnaires to ensure that they are qualified to enter the study and are likely to have normal gastric emptying rates. Informed consent/assent will be obtained.

Breath samples will be collected by children blowing into test tubes before and after eating a 13C-Spirulina GEBT meal. Breath samples will be collected and the test will be administered via telehealth or at one of the children's hospital clinics.

Researchers will analyze results from different age groups to see if there are differences in normal gastric emptying in younger/older children and boys/girls.

Inclusion Criteria:

• Children ages 7 to 18 years who provide written assent and whose parents provide written consent for participation
• Healthy and without any significant prior medical history or developmental delays
• Able to eat the test meal and provide breath samples.-

Exclusion Criteria:

Any known physician-diagnosed medical (gastrointestinal, pancreatic, or liver disease that may cause malabsorption, neurological) or psychiatric disease

• Chronic pulmonary disease including moderate/severe reactive airway disease requiring treatment with a daily inhaler
• Type 1 or 2 Diabetes
• Chronic gastrointestinal symptoms or functional gastrointestinal disorders
• Mental retardation or pervasive developmental disorder
• Currently receiving prescription drug therapy that may affect gastric motor function or sensation
• Any over-the-counter or herbal supplements that may affect gastric motor function or sensation
• Allergy to Spirulina, egg, milk, wheat or gluten (unless consuming gluten free crackers with the test meal) or known intolerance to any ingredient in the test meal