Adaptation of Diagnostic Tests for Evaluation of Abdominal Pain or Chronic Diarrhea in Children With ASDs

Tests That May Be Difficult to CompleteTests That May Be Easier to Complete (Be Selective)
Noninvasive tests
 Upper gastrointestinal series with small-bowel follow-throughStool for enteric pathogens, ova/parasites, Giardia antigen, C difficile toxin
 72-h fecal-fat collectionStool: guaiac, electrolytes/osmolarity (if secretory diarrhea), split and neutral fat, calprotectin, lactoferrin, trypsinogen, α-1-antitrypsin, elastase
 LBTSerum: electrolytes, liver function tests
Assessment of nutritional status (if appropriate): anthropometry, 25-OH vitamin D
Abdominal radiograph (assessment of bowel gas pattern and retention of stool)
Tests that require anesthesia
 —Upper endoscopy: biopsy looking for enteritis; disaccharidase assay (lactase or sucrase–isomaltase deficiency); secretin test
Colonoscopy: biopsy looking for colitis