The purpose of this study is to collect information regarding lot-to-lot variability in 13C-Spirulina test meal lets and within-subject biological variability.

In this study participants will participate in one or two arms of the study. In one arm the participants will be administered GEBT tests that contain different 13C-Spirulina/Egg mix drug lots. In the second arm, the participants will be administered GEBT tests from the same 13C-Spirulina/Egg mix drug lot. All GEBT kit lots will be administered according to the FDA-approved labeling.

Inclusion Criteria:

• Males and females, 18-85 years old at time of signing the informed consent form
• Ability to eat test meal and provide breath samples

Exclusion Criteria:

• History or physical exam suggestive of systemic disease such as diabetes mellitus or pathophysiologic disorders such as renal failure, chronic heart disease, chronic respiratory disease, liver disease, or malabsorption.
• History of abdominal surgery except appendectomy
• Use of any medications that may alter gastric motility within two days of the study
• Use of narcotics or anticholinergics within two days of the study
• Females on hormone replacement therapy other than birth control medications
• Pregnancy
• Intolerance or allergy to any component of GEBT test meal
• History of neurologic or psychiatric disorders