Suspected diagnosis	Testing to consider	Clinical features of patient
Gastric bloating
Functional dyspepsia	Helicobacter pylori testing (urea breath testing most cost-effective relative to endoscopy; stool antigen testing is less expensive and also a reasonable option; serologic tests are least accurate)7,8,19	If younger than 55 years with no alarm symptoms, test-and-treat strategy for H. pylori detection and eradication is safe and cost-effective8
	EGD	If 55 years or older or with alarm symptoms (Table 1), EGD is indicated
Disorders of accommodation	Gastric accommodation study (only available at specialized centers)	Diagnosis is difficult, and treatments are only minimally effective
		Testing is of limited utility
Gastroparesis	Gastric emptying study8 (recommended only if gastroparesis is strongly suspected; should not be routinely obtained in functional dyspepsia)	If diabetes mellitus or recent viral illness and negative EGD, consider gastroparesis
Gastric outlet obstruction	EGD	If early satiety or vomiting, or if suspected or known history of peptic ulcer disease, rule out gastric outlet obstruction with EGD
Small bowel bloating
IBS	Celiac serology	Consider testing for celiac disease in patients with diarrhea-predominant or mixed-presentation IBS, or if local prevalence of celiac disease > 10%20,21
	Colonoscopy	If 55 years or older, alarm symptoms (Table 1), or routine screening is due, colonoscopy indicated16
Celiac disease	Celiac serology*	Intestinal symptoms of celiac disease (diarrhea, weight loss, abdominal bloating and distention, gas) are less common than extraintestinal symptoms (anemia, dermatitis herpetiformis, oral lesions, osteoporosis/osteopenia)22
	Must include tissue transglutaminase and total IgA (to rule out IgA deficiency)
	If IgA deficiency is present, test with deamidated gliadin
	Serologic testing should ideally be confirmed by biopsy
SIBO	Lactulose hydrogen breath testing (appropriate only for patients with risk factors for SIBO)	Risk factors for SIBO: structural abnormalities (small bowel diverticula, strictures, surgical blind loops, ileocecal valve resection); disordered motility (scleroderma, type 1 diabetes, use of opioids); acid suppression (chronic proton pump inhibitor use, achlorhydria, gastric resection)4
Functional abdominal distention	Testing usually not necessary	Subjective symptoms of recurrent abdominal pressure with objective increases in abdominal girth
		More likely related to abdominal wall muscle relaxation than to retained gas9
Functional abdominal bloating	Testing usually not necessary	Subjective symptoms of recurrent abdominal pressure, sensation of trapped gas
		Typically worsens throughout day and after meals, improves overnight9
Bloating with constipation
Chronic idiopathic constipation (functional constipation, constipation-predominant IBS)	Rule out dyssynergic defecation (see example in this table) and secondary constipation	Incomplete evacuation
		Straining with defecation
		Manual removal of stool
		History of sexual or physical abuse6,15,16
Secondary constipation	Hypothyroidism, diabetic neuropathy, hypomagnesemia, hypokalemia, and hypercalcemia	Inquire about medications (calcium-containing antacids, iron supplements, anticholinergics, opioids)
Dyssynergic defecation (pelvic floor dysfunction)	Careful perineal and rectal examination (often sufficient to guide further testing)	Incomplete evacuation
	Anorectal manometry (may be required to justify insurance coverage of treatment)	Straining with defecation
		Manual removal of stool
		History of sexual or physical abuse6,15,16
Slow transit constipation	Colonic transit study (consider only after ruling out dyssynergic defecation)	Rare condition
		False-positive results not uncommon
Belching
Gastric belching	Testing usually not necessary but can be reliably diagnosed by manometry and impedance testing7	Rapid eating and gum chewing, which may cause excessive air swallowing; lower esophageal sphincter relaxes with belching7
Supragastric belching	Testing usually not necessary but can be reliably diagnosed by manometry and impedance testing7	Patients who are belching during conversation; worse when discussing symptoms and better when distracted; lower esophageal sphincter does not relax with belching7
Aerophagia (“air swallowing”—now considered a historical term)†	Testing not necessary	Anxiety, rapid eating, and chewing gum may cause excessive air swallowing, both supragastric and gastric (see above)23