Gastroparesis is a condition in which patients experience symptoms of delayed gastric emptying in the absence of an actual physical blockage. The most common symptoms are nausea, vomiting, early satiety, bloating, abdominal pain, and postprandial fullness. Assessing gastric emptying delay is essential to diagnosing gastroparesis. In clinical research, the definition of gastroparesis is delayed gastric emptying as detected by clinical testing and the presence of symptoms of nausea and/or vomiting, postprandial fullness, early satiety, bloating, or epigastric pain for more than 3 months. The etiologies of gastroparesis are most often idiopathic, diabetic, or postsurgical, but can also be autoimmune, paraneoplastic, or neurologic. The condition is generally assessed in the outpatient setting, but some patients become severely ill with intractable vomiting and dehydration and are hospitalized. Hospitalizations for gastroparesis increased by 158 percent between 1995 and 2004. In individuals with diabetes and gastroparesis, digestion of food is unpredictable, and wild swings in blood glucose can increase morbidity and necessitate medical care. Constipation is common, occurring in 15 to 20 percent of the U.S. population. Multiple professional societies define constipation (with slight variation) as fewer than two bowel movements per week or a decrease in a person's normal frequency of stools accompanied by straining, difficulty passing stool, or passage of hard solid stools. Physicians must assess patients with symptoms of constipation via their medical history and a physical examination to exclude malignant or organic causes of constipation. Clinicians should ask about warning signs such as new onset of symptoms, obstructive symptoms, rectal bleeding, unintentional weight loss, or family history of early colon cancer. A rectal examination can help to delineate rectal function and tone and exclude a low rectal cancer. Clinicians should perform a colonoscopy on all patients over 50 who have never received a screening colonoscopy, and those who have fecal occult blood, iron deficiency anemia, or any other warning signs. However, the yield of colonoscopy in patients with constipation with warning signs is low. Once a physician has eliminated all organic causes for constipation, a diagnosis of functional constipation is appropriate. Our objective was to summarize the evidence on how useful current testing modalities for gastric and colonic motility are for diagnosing disease. Key Questions addressed include: KQ 1. In the evaluation of gastric dysmotility, how does the WMC alone compare with gastric scintigraphy, antroduodenal manometry, and endoscopy, in terms of diagnostic accuracy of gastric emptying delay, accuracy of motility assessment, effect on treatment decisions, effect on patient-centered outcomes, harms, and effect on resource utilization? KQ 2. When gastric scintigraphy, antroduodenal manometry, or endoscopy is used in the evaluation of gastric dysmotility, what is the incremental value of also using WMC, in terms of diagnostic accuracy of gastric emptying delay, accuracy of motility assessment, effect on treatment decisions, effect on patient-centered outcomes, harms, and effect on resource utilization? KQ 3. In the evaluation of colonic dysmotility, how does WMC alone compare with ROM and scintigraphy in terms of diagnostic accuracy of slow-transit constipation, accuracy of motility assessment, effect on treatment decisions, effect on patient-centered outcomes, harms, and effect on resource utilization? KQ 4. When an ROM or scintigraphy is used in the evaluation of colonic dysmotility, what is the incremental value of also using WMC, in terms of diagnostic accuracy of slow-transit constipation, accuracy of motility assessment, effect pm treatment decisions, effect on patient centered outcomes, harms, and effect on resource utilization?