Test	Comments
Antroduodenal manometry	Can be useful in patients with unexplained vomiting; can assess fasting and postprandial phases; invasive procedure requiring expertise to perform and interpret
Breath test	Breath tests using a nonradioactive isotope carbon-13 bound to a digestible substance have been validated for measuring gastric emptying; noninvasive but requires normal small intestinal absorption, liver metabolism, and pulmonary excretion functions
Electrogastrography	Noninvasive adjunct to gastric emptying scintigraphy as part of a comprehensive evaluation of patients with refractory symptoms
Gastric emptying scintigraphy	Recommended test for diagnosis of gastroparesis; quantifies the emptying of a physiologic caloric meal; able to assess liquid and solid emptying; minimal radiation exposure
Magnetic resonance imaging	Noninvasive; primarily measures emptying of liquids; expensive and time consuming
Ultrasonography	Noninvasive; operator dependent
Upper gastrointestinal series	Greatest value is the ability to exclude mucosal lesions and mechanical outlet obstruction; moderate radiation exposure