Stool routine microscopy (stool examination under microscope)

  • Analysis of the stool sample under microscope can reveal parasites or blood cells which indicates infection.
  • Cholera micro-organisms (bacteria) can be identified by a special method called ‘hanging drop’ method.

Stool culture

  • Done in patients with dysentery, high fever, prolonged illness and blood cells in stools.
  • The causative germ grows in an artificial medium and identified by various physical and chemical methods so that a specific medicine against it can be given.

Blood investigations

  • Blood tests are not needed usually but they are helpful and may be prescribed by your doctor in a particular condition.
  • Infections such as Clostridium, Giardia infections and other parasites may be diagnosed by ELISA tests as well.
  • Blood culture might be needed to detect bacteria present in blood.

Special tests

  • Endoscopy (visualization of gastrointestinal tract by a tube): Parts of digestive system are visualized directly by putting in a flexible fiberoptic tube via mouth for upper digestive tract) or anus (for lower digestive tract). The intestinal tract is visualized for any hallmark lesion like ulcers caused by a germ (Clostridium difficile, E. histolytica), taking secretions for microscopy and culture and taking biopsy.


  • Barium studies :Intestinal tract is outlined by a dye (barium) which can be visualized in x-ray films. These studies are helpful in diagnosing tuberculosis of abdomen, tumors of digestive tract, conditions like ulcerative colitis and diverticulum disease.
  • D – Xylose, lactose intolerance and fat malabsorption tests are useful tests in cases of chronic diarrhea to diagnose improper or lack of absorption of various nutrients in intestine and food allergies.
  • Biopsy : A small piece of the lining of digestive tract is obtained with help of endoscopes. It can be examined further by various tests to diagnose tumors and other conditions of digestive tract.