Stool Examination

Bowel movement (defecation) is the excretion of feces (stool, excrement, feces, faeces) from the human digestive tract. The stool consists of undigested food components, secretions of the digestive tract (digestive juices), intestinal epithelia (intestinal mucosal cells), bile pigments and to a large extent intestinal bacteria (up to about 20% of the stool mass).

The stool frequency (stool frequency) in healthy individuals ranges from three times a day to three times a week. A stool frequency of more than three times a day is called diarrhea (diarrhea), and a stool frequency of less than three times a week is called constipation (constipation).

Stool consistency varies between hard and soft (the stool should be formed) and varies greatly from individual to individual. This is especially dependent on the ingested food. The first part of the stool (main stool) is usually firmer than the subsequent stool, which comes about a minute after the initial evacuation. The stool should float on water, at least initially.

Medically desirable are large stools, i.e., high in fiber.Stool color is yellow-brown. This is mainly caused by stercobilin (one of the degradation products of hemoglobin/blood pigment). The stool color is further determined by the ingested food (the more meat the darker), intake of medications (e.g. black stool with iron supplements) and/or diseases of the gastrointestinal tract (gastrointestinal tract).

The stool odor can be described as aromatic if the colon (large intestine) is normally colonized with germs. It is perceived as malodorous in putrefactive dyspepsia (increase in putrefactive processes in the small and especially colon/large intestine as a result of inadequate protein digestion); it is perceived as pungent in fermentative dyspepsia (inadequate breakdown of carbohydrates/sugars in the upper small intestine and resulting increased bacterial fermentation by gas-forming bacteria in the small and large intestine). Fatty stools (steatorrhea or pancreatic stools) are also perceived as having a pungent odor.The stool quantity averages 150-250 g (stool quantities of 100 to 500 g are to be considered physiological), vegetarians have stool weights of up to 350 g due to the higher fiber content of the diet. Increased stool weight occurs in cases of malabsorption (inadequate absorption of food ingredients), celiac disease (gluten-induced enteropathy; chronic disease of the small intestinal mucosa (mucous membrane of the small intestine) based on hypersensitivity to the cereal protein gluten) and fatty stools.

Pathologic (abnormal) stool admixtures may include:

  • Mucus/mucus buildup – in irritable bowel syndrome (IBS), enteritis (inflammation of the bowel).
  • Food residues – in disturbed digestion or enzyme deficiency.
  • Blood – visible and occult (hidden, invisible).
  • Worms or worm eggs – in case of infestation with parasites.
  • Pus (pus) – in cases of diverticulitis (inflamed intestinal protrusions), progressive (advanced) tumors, parasite infestation.

Typical stool tests (stool diagnostics) are: