DFS & Fecalysis

• Stool


  Human feces
• Faeces/Feces


  Plural of Latin term faex meaning residue
• Faeces/Feces


  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
• Composition of feces


  • ¾ water, ¼ solid
  • Undigested and Unabsorbed food
  • Intestinal secretions, Mucous
  • Bile pigments and Salts
  • Bacteria and Inorganic material
  • Epithelial cell, Leukocytes
• Stool collection


  1. Universal Precautions

  2. Stool should be collected in a dry, sterilized, wide mouthed container

  3. It should be uncontaminated with urine or any other body secretions

  4. Properly named and always a fresh sample should be tested
• Macroscopic examination of stool


  • Volume <200 gms/day
  • Color
  • Consistency
  • Odor
  • Blood, Mucous
  • Parts of parasite and adult parasite
• Normal color of human fecal matter


  Yellowish brown in color which results 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
• Color of feces in infants


  • Exclusively breast-fed infants pass loose and green or pasty and yellow stools
  • Infants fed on cow's milk preparations pass stools of a paler yellow color and of a much firmer consistency
  • Babies fed on newer modified cow's milk preparations have clay colored or greenish stools
  • Some healthy children may pass frequents, loose stools containing undigested vegetable matter called as Toddler's diarrhea
• Odor of stool


  • 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
  • A foul odor is caused by degradation of undigested protein and excessive carbohydrate intake
  • Sickly sweet odor is produced by undigested lactose
• Stool characteristics and associated conditions


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

  • Round worm
  • Hook worm
  • Tape worm
  • Pin worm
  • Whipworm
• Microscopic examination of stool

  1. Materials: Microscopic slides, Cover slips, Sodium chloride solution, Lugol's iodine solution, Wooden applicator, Fresh stool, Gloves

  2. Slide preparation: A drop of warm Saline or Lugol's Iodine is placed over a clean microscopic slide, About 2mg of stool sample should be taken and mixed with soln placed over the slide, Coverslip is placed avoiding air bubbles, Examined under Microscope
• Pinworm egg collection


  Eggs of pinworm – Enterobius vermicularis rarely appear in stools, These are usually collected in the folds of the skin in perianal region, Collection: Cotton swab/ Plaster patch – anus especially in early morning – dipped in Saline – Observed
• Examination of parasites


  • Warm stools are best for detecting Ova or parasites, Do not refrigerate the specimen, Because of cyclic life cycle of parasites, three separate random stool specimens are recommended for examination
• Normal values in stool examination


  • Undigested food materials – none to small amount
  • Starch – None
  • Eggs, Cysts, Parasitic fragments – None
  • Yeasts – None
  • Leukocytes – None
• Leukocytes in stool


  • Large amounts of leukocytes is suggestive of Chronic Ulcerative Colitis, Chronic Bacillary Dysentery, Localised Abscess, Fistulas
  • Mononuclear Leukocytes appear in Typhoid
  • Polymorphonuclear Leukocytes appear in Shigellosis, Salmonellosis, Invasice E. coli diarrhea, Ulcerative Colitis
  • Absent Leukocytes in 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 1011 organisms per gram wet weight as normal flora, Whereas gut bacterial pathogens rarely exceed 105 organisms per gram
• Stool culture


  1. Culture media usually used is of AGAR and is done aerobically

  2. XLD Agar media – Salmonella Shigella

  3. TCBS Agar media- Cholera

  4. MacConkey media - Yersinia enterocolitica

  5. Campylobacter culture media for Campylobacter species

  6. The mainstay of diagnosis of bacterial infections of the gut is by culture
• Hanging drop test


  Place a drop stool in the center of a coverslip, Place a drop of water / vaseline at each corner of the coverslip, Invert a slide with a central depression over the coverslip, The coverslip will stick to the slide and when the slide inverted the drop of bacterial is culture will be suspended in the central depression of the slide, Examine microscopically (X100) for motile organisms
• Chemical examination of stool


  • Water - Up to 75%
  • pH - 5.8 to 7.5
  • Occult blood, RS – Negative
  • Bile - Negative in Adults, Positive in Children
  • Sodium - 5.8 to 9.8 mEq/24hrs
  • Chlorides - 2.5 to 3.9 mEq/24hrs
  • Potassium - 15.7 to 20.7 mEq/24hrs
  • Lipids / Fatty acids - 0 to 6 gms/24hrs
  • Nitrogen - <2.5g/24hrs
• Increased pH - Alkaline


  • Colitis
  • Antibiotic use
  • Villous adenoma
  • Excess Protein in diet
• Decreased pH - Acidic


  • Carbohydrate Malabsorption
  • Fat Malabsorption
  • Disaccharidase deficiency
• Occult blood - Benzidine test


  Peroxidase action of hemoglobin in stool
• Microscopic examination of fecal sample


  1. Depression of the slide

  2. Examine microscopically (X100) for motile organisms
• PORK TAPEWORM


  Parasite found in fecal sample
• BEEF TAPEWORM


  Parasite found in fecal sample
• POLAR ENDS


  Characteristic of parasite found in fecal sample
• PERIANAL REGION


  Location of parasite found in fecal sample
• PROTOZOA


  Microscopic single-celled organism found in fecal sample
• CYTOPLASM


  Part of protozoan cell found in fecal sample
• KARYOSOME


  Part of protozoan cell found in fecal sample
• CYST WALL


  Part of protozoan cell found in fecal sample
• PERIPHERAL CHROMATIN


  Part of protozoan cell found in fecal sample
• INGSTED RBC


  Part of protozoan cell found in fecal sample
• PROTOZOAN


  Microscopic single-celled organism found in fecal sample
• Contaminated food or water from stool of patient

  Leads to growth of bacteria
• NIEVES, KATHLEEN B.