DFS & Fecalysis

• Stool

  Human feces
• Stool


  Human feces
• Faeces/Feces


  Plural of Latin term faex meaning residue
• Faeces/Feces


  Plural of Latin term faex meaning residue
• Faeces/Feces is a waste residue of indigestible materials of an animal's digestive tract expelled through the anus during defecation
• Meconium


  Newborn's first feces
• Scatology or Carpology


  Study of the feces
• Stool composition is ¾ water, ¼ solid
• Components of stool


  • Undigested and Unabsorbed food
  • Intestinal secretions, Mucous
  • Bile pigments and Salts
  • Bacteria and Inorganic material
  • Epithelial cell, Leukocytes
• Stool collection


  • Universal Precautions
  • Collected in a dry, sterilized, wide mouthed container
  • Uncontaminated with urine or any other body secretions
  • Properly named and always a fresh sample should be tested
• Macroscopic examination of stool


  • Volume
  • Color
  • Consistency
  • Odor
  • Blood, Mucous
  • Parts of parasite and adult parasite
• Normal color of human fecal matter


  Yellowish brown resulting from a combination of bile and bilirubin
• Variations in stool color


  • Bright Red/Maroon
  • Blood streak
  • Yellow
  • Green
  • Black
  • Blue
  • Tan/Clay
  • White
  • Pale greasy
• Stool color in infants


  • Exclusively breast-fed infants - loose and green or pasty and yellow
  • Infants fed on cow's milk preparations - paler yellow color and of a much firmer consistency
  • Babies fed on newer modified cow's milk preparations - clay colored or greenish
  • Some healthy children - frequent, loose stools containing undigested vegetable matter (Toddler's diarrhea)
• Normal stool odor


  Depends on the pH of the stool and INDOLE and SKETOLE are the substances that produce normal odor formed by Intestinal bacterial fermentation and putrefaction
• Foul stool odor


  Caused by degradation of undigested protein and excessive carbohydrate intake
• Sickly sweet stool odor


  Produced by undigested lactose
• Stool characteristics suggestive of certain conditions


  • Diarrhea mixed with mucous and blood - Typhoid, Amoebiasis, Typhus, Large bowel Carcinoma
  • Diarrhea mixed with mucous and Pus - Ulcerative Colitis, Regional Enteritis, Shigellosis, Salmonellosis, Acute diverticulitis, Intestinal TB
  • Pasty stool with high fat content - CBD Obstruction, Cystic fibrosis-butter stool
  • Translucent gelatinous mucous clinging to the surface of the formed stool - Spastic Constipation, Excessive straining, Mucous colitis
  • Rice water stools which is colorless and almost devoid of odor - Cholera
  • Stools like Redcurrant jelly - Intussusception
• Common parasites found in stool


  • Round worm
  • Hook worm
  • Tape worm
  • Pin worm
  • Whipworm
• Materials required for microscopic examination of stool


  • Microscopic slides
  • Cover slips
  • Sodium chloride solution
  • Lugol's iodine solution
  • Wooden applicator
  • Fresh stool
  • Gloves
• Slide preparation for microscopic examination


  1. A drop of warm Saline or Lugol's Iodine is placed over a clean microscopic slide

  2. About 2mg of stool sample should be taken and mixed with solution placed over the slide

  3. Coverslip is placed avoiding air bubbles

  4. Examined under Microscope
• Concentration method to detect ova


  Used to concentrate parasite eggs/cysts in stool sample
• Pinworm egg collection


  Eggs of pinworm - Enterobius vermicularis rarely appear in stools, usually collected in the folds of the skin in perianal region using cotton swab or plaster patch
• Warm stools are best for detecting ova or parasites, do not refrigerate the specimen
• Feces is a waste residue of indigestible materials of an animal's digestive tract expelled through the anus during defecation
• Meconium

  Newborn's first feces
• Scatology or Carpology


  Study of the feces
• Feces is composed of approximately 3/4 water and 1/4 solid
• Three separate random stool specimens are recommended for examination due to cyclic life cycle of parasites
• Normal values in stool microscopic examination


  • Undigested food materials - none to small amount
  • Starch - None
  • Eggs, Cysts, Parasitic fragments - None
  • Yeasts - None
  • Leukocytes - None
• Significance of leukocytes in stool

  • Large amounts - Chronic Ulcerative Colitis, Chronic Bacillary Dysentery, Localised Abscess, Fistulas
  • Mononuclear Leukocytes - Typhoid
  • Polymorphonuclear Leukocytes - Shigellosis, Salmonellosis, Invasice E. coli diarrhea, Ulcerative Colitis
  • Absent Leukocytes - Cholera, Viral diarrhea, Non-specific diarrhea, Amoebic Colitis, Giardiasis
• Normal microbial flora of GI tract


  • Gram -ve - E. coli, Enterobacter, Proteus, Pseudomonas aeruginosa, Bacteroides
  • Gram +ve - Clostridia, Lactobacilli, Enterococci, Anaerobic streptococci
• Human feces contain approximately 10^11 organisms per gram wet weight as normal flora, whereas gut bacterial pathogens rarely exceed 10^5 organisms per gram