Gastroparesis Registry 2

Inclusion Criteria: * Symptoms of gastroparesis of at least 12 weeks duration (do not have to be contiguous) with varying degrees of nausea, vomiting, early satiety, post-prandial fullness, and/or abdominal pain * An etiology of either diabetic, idiopathic, or post-Nissen fundoplication gastroparesis * Gastric emptying scintigraphy of solids and liquids test using 4 hours Egg Beaters® protocol within the last 6 months with either: * Abnormal gastric emptying rate defined as an abnormal 2 hour (\>60% retention) and/or 4 hour (\>10% retention) result based on a 4-hour scintigraphic low fat Egg Beaters® gastric emptying study performed at a GpCRC clinical center. * Patients with a normal gastric emptying rate but with symptoms of gastroparesis may be enrolled and classified as possible gastroparesis or gastroparesis-like with normal gastric emptying * Age at least 18 years at initial screening visit * Upper endoscopy results within last 2 years Exclusion Criteria: * Inability to comply with or complete the gastric emptying scintigraphy test (including allergy to eggs) * Presence of other conditions that could explain the patient's symptoms: * Pyloric or intestinal obstruction as determined by endoscopy, upper GI series or abdominal CT scan * Active inflammatory bowel disease * Known eosinophilic gastroenteritis * Primary neurological conditions that could cause nausea and/or vomiting such as increased intracranial pressure, space occupying or inflammatory/infectious lesions * Acute liver failure * Advanced liver disease (Child's B or C; a Child-Pugh-Turcotte (CPT) score of ≥7 ) * Acute renal failure * Chronic renal failure (serum creatinine \>3 mg/dL) and/or on hemodialysis or peritoneal dialysis * Total or subtotal (near complete) gastric resection, esophagogastrostomy, gastrojejunostomy, or gastric bypass. Note: patients with prior fundoplication will be eligible for enrollment. * Any other plausible structural or metabolic cause * Any other condition, which in the opinion of the investigator would interfere with study requirements * Inability to obtain informed consent