The child who excretes small pellets of stool and seemingly uncontrolled liquid stool most likely has a large burden of stool in his colon. The stool has hardened, making it hard to pass, and resulting in small, formed or hard, pellets of stool. Liquid stool is leaking around the large amount of stool in the colon and may be uncontrollable. The stool has stretched the rectal vault and reduced the child’s sensation and control. An abdominal x-ray would quickly reveal a significant impaction of stool. A rectal biopsy is used to assess for a disease such as Hirschsprung’s in infancy and is less appropriate than an abdominal x-ray. Gluten sensitivity testing is not going to diagnose or resolve the current problem of impaction. A metabolic panel would not reveal the impaction.