Pediatric Irritable Bowel Syndrome (IBS) Workup

Updated: Jun 06, 2022
  • Author: Mohammad F El-Baba, MD; Chief Editor: Carmen Cuffari, MD  more...
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Laboratory Studies

Laboratory tests

No specific laboratory markers are noted for irritable bowel syndrome (IBS). [1] Patients who have characteristic symptoms and meet the Rome criteria for irritable bowel syndrome (see History) do not require a thorough diagnostic evaluation. A more aggressive approach is recommended for individuals with atypical symptoms, those with a rapidly progressive course, or when the index of suspicion for an organic disease is high.

In classic cases, a limited screen for organic disease is reassuring and should consist of the following:

  • Complete blood cell (CBC) count

  • Erythrocyte sedimentation rate

  • Stool studies for ova and parasites

  • Stool cultures and stool Clostridium difficile toxin assay, if clinically indicated

  • A breath hydrogen test or a trial of dietary lactose restriction to exclude lactose intolerance

The following laboratory tests are indicated in special instances:

  • Lead level assessment

  • Celiac serologic tests

  • Serum immune markers for inflammatory bowel disease

  • Thyroid function tests

  • Tests for Helicobacter pylori (ie, serum antibody titers, urea breath test)

Studies have suggested that determining the level of fecal calprotectin in stool may help distinguish irritable bowel syndrome from inflammatory bowel disease. A negative calprotectin result favors a functional disorder rather than an inflammatory process, thereby sparing many patients from having extensive work-up and invasive investigations, such as colonoscopy. [24]

Other tests

Gastrointestinal manometry can assist in evaluating patients in whom gastroparesis or intestinal pseudo-obstruction is suspected.

Anorectal manometry is useful to screen patients in whom Hirschsprung disease is suspected.


Imaging Studies

Plain abdominal radiography is recommended for patients with pain-predominant symptoms. Perform plain abdominal radiography during a pain episode to exclude intermittent obstruction.

An upper gastrointestinal study (UGIS) with small-bowel follow through is a useful study if Crohn disease or celiac sprue is suggested.

Barium enema can be useful for patients in whom Hirschsprung disease or congenital structural anomalies of the colon are suspected. Barium enema is also indicated in older patients (>50 y) because of the increased likelihood of colonic neoplasms.

Gastric scintigraphy is indicated for selected patients to evaluate for gastroparesis.

Abdominal ultrasonography is suggested for patients in whom biliary disease is suspected. It has high sensitivity and specificity for gallstones. It can also detect gallbladder wall thickening.



Sigmoidoscopy or complete colonoscopy is useful to evaluate for inflammatory conditions such as ulcerative colitis and microscopic colitis. Severe colitis noted during colonoscopy is shown in the image below.

Pediatric Irritable Bowel Syndrome (IBS). Severe c Pediatric Irritable Bowel Syndrome (IBS). Severe colitis noted during colonoscopy. The mucosa is grossly denuded, with active bleeding observed. This patient's colon was resected very shortly after this view was obtained.

Upper endoscopy with small-intestinal biopsies is recommended in patients in whom peptic ulcer disease, Helicobacter pylori infection, Crohn disease, celiac disease, or other malabsorption conditions are suspected.