Finals Lab 1

• Hemin test


  Test to detect the presence of blood
• Materials needed for dermal puncture


  • Lancet
  • Glass slide
  • Sodium chloride (NaCl)
  • Glacial acetic acid
  • Alcohol lamp
  • Microscope
• Hemin test procedure

  1. Place 1-2 drops of blood on a clean glass slide

  2. Add a pinch of NaCl and 1-2 drops of glacial acetic acid, mix thoroughly

  3. Heat the mixture until it begins to boil

  4. Allow the slide to cool before placing the cover slip

  5. Examine the slide under the microscope
• Trapped bubbles will affect what you will see in the microscope
• Principle of hemin test


  The globin gets denatured by heating with acetic acid; while heme is converted to oxidized heme called hematin. Hematin combines with halogens such as chloride forming the hemin crystals
• Positive result of hemin test


  Hemin crystals
• Benzidine test


  Test to detect the presence of blood
• Benzidine test procedure


  1. Add 1 mL of Benzidine reagent to a test tube

  2. Add 10 drops of dilute blood

  3. Add 5 drops of 3% hydrogen peroxide

  4. Note the color of the solution
• Principle of benzidine test


  The peroxidase activity of hemoglobin decomposes hydrogen peroxide, releasing nascent oxygen which in turn oxidizes benzidine
• Positive result of benzidine test


  A deep blue color appearing within 15 seconds
• Guaiac test


  Test to detect the presence of blood
• Guaiac test procedure

  1. Add 1 mL of dilute blood to a test tube

  2. Add drops of guaiac solution until the solution becomes turbid

  3. Add 1% H2O2 dropwise until a blue color appears
• Principle of guaiac test


  When the hydrogen peroxide is dropped into the mixture, it oxidizes the alpha-guaiaconic acid to a blue-colored quinone. Heme, a component in blood, catalyzes this reaction giving a rapid result
• Positive result of guaiac test


  A deep blue color
• Physical examination of urine

  Observe and take note of the volume, color, clarity, and odor of the urine specimens
• Factors influencing urine volume

  Water intake (body state of hydration)<|>Kidney excretion<|>Fluid intake<|>Fluid loss from nonrenal sources<|>Variations in the secretion of antidiuretic hormones<|>The need to excrete increased amounts of dissolved solids (e.g. glucose or salts)
• Chemical examination of urine


  Use a urine strip to test the chemical properties of the urine