Routine Stool Examination (Lab)

• SPECIMEN COLLECTION

  • Clean, dry, wide-mouthed containers
  • Sealed and sent to the laboratory immediately after collection
  • Preserved specimens can usually be kept at a room temperature
  • Large gallon containers for 24-, 48-, and 72-hour stool collections for fecal fat and urobilinogen; specimens normally refrigerated throughout collection period
  • Carefully give instruction to the patient on how to properly collect their stool
  • Let the feces go on the side of the toilet and use the scooper to collect a pea-sized amount [avoid contamination with water]
• ROUTINE STOOL EXAMINATION

  • Physical analysis
  • Chemical analysis
  • Microscopic analysis
• Physical Examination (stool) - consistency, color, gross abnormalities
• CONSISTENCY OF STOOL

  • Degree of moisture in a stool specimen

  • Formed, semi-formed, soft, loose, or watery
• • The normal color of the stool is brown.
• hard, dark brown, conspicuously fibrous
• soft, black, fiber scanty to moderate
• mushy, brown, colloidal (homogeneous)
• loose, pale brown, scanty mucus
• diarrheic, clay, much mucus
• watery, liquid, yellow, mucus with scanty blood
• formed, red-brown, other (e.g., blood, barium)
• semi formed, green, other
• black

  • upper git bleeding
  • iron therapy
  • charcoal
  • bismuth (antacids)
• red

  • lower git bleeding
  • ingestion of beets & food coloring
  • rifampin
• green

  • biliverdin
  • oral antibiotics
  • green vegetables
• pale yellow, gray, white

  • bile duct obstruction
  • barium sulfate
• presence of mucus, blood streak

  • dysentery
  • malignancy
• GROSS ABNORMALITIES

  • Adult worms (ascaris, tapeworms), proglottids (egg laying segments of adult tapeworms), and parasitic indications (pus and mucus)
  • Samples containing adult worms (ascaris, tapeworms [thinner]) may be carefully washed through a wire screen. This process allows for the retrieval and examination of the parasites for identification purposes
• CHEMICAL EXAMINATION

  • Detection of occult blood (hidden blood)
  • — Fat, urobilinogen (gives stool normal color) could be tested as well, not just occult blood

  Hema-screen Guiac Slide Test Kit

  • Hema-screen slide
  • Hema-screen developer (<6% H2O2)

  Results

  • (+) any trace of blue coloration
  • (-) no detectable blue coloration
• INTERFERENCE OF FOBT : False-positive

  • Aspirin and anti-inflammatory medications
  • Red meat (beef or goat)
  • Horseradish
  • Raw broccoli, cauliflower, radishes, turnips
  • Melons
  • Menstrual and hemorrhoid contamination
• INTERFERENCE OF FOBT : False-negative

  • Vitamin C > 250 mg/d
  • Iron supplements containing vitamin C
  • Failure to wait specified time after sample is
  • applied to add the developer reagent
• MICROSCOPIC EXAMINATION

  • To detect the presence of parasites in a stool specimen
  • It can also reveal artifact (microscopic structures that can be seen in the stool)
  • It should be performed on a fresh specimen
• • NOPS – No ova and/or parasite seen
  • NIPS – No intestinal parasite seem
• DIRECT FECAL SMEAR

  • About 2 mg of stool (amount forming a low cone at the tip of an applicator stick)
  • 0.85% sodium chloride solution (NSS)
  • Cover with cover slip - Primary useful in the detection of motile protozoan trophozoites (pale and transparent)
  • Weak iodine solution (Lugol’s and D’Antoni) are temporary stain to demonstrate nuclei [help color the nuclei]
• • Helminth eggs and larvae can be detected using this preparation
  • Cytoplasm: Golden Yellow
  • Nucleus: Pale and refractile
  • Glycogen: Deep brown