LABORATORY DIAGNOSIS

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LABORATORY DIAGNOSIS

• PERIPHERAL BLOOD SMEAR

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PERIPHERAL BLOOD SMEAR

• A properly prepared blood smear is essential to
  accurate assessment of cellular morphology
• The wedge smear is the most convenient and
  commonly used technique for making PBS

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PERIPHERAL BLOOD SMEAR
Wedge technique of making PBS
A. Correct angle to hold spreader slide
B. Blood spread across width of slide
C. Completed wedge smear
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PERIPHERAL BLOOD SMEAR

• Characteristics
• About two thirds to three fourths of the slide is
  covered by the smear
• It is very rounded at featheredge (thin portion),
  not bullet shape
• Lateral edges of the smear should be visible

Well-made PBS
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PERIPHERAL BLOOD SMEAR

• Characteristics
• It is smooth without irregularities, holes, or
  streaks
• When the slide is held up to light, the
  featheredge of the smear should have a rainbow
  appearance
• The whole drop is picked up and spread

Well-made PBS
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PERIPHERAL BLOOD SMEAR

• Examples of unacceptable smears

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PERIPHERAL BLOOD SMEAR

• Examples of unacceptable smears

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PERIPHERAL BLOOD SMEAR

• Staining of PBS
• Purpose of staining is to identify cells and
  recognize morphology easily through the
  microscope
• Uses Wright stain or Wright-Giemsa stain which
  contain both eosin and methylene blue ?
  polychrome stains

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PERIPHERAL BLOOD SMEAR

• Optimally stained smears have the following
  characteristics

1. RBCs should be pink to salmon in color
2. Nuclei are dark blue to purple
3. Cytoplasmic granules of neutrophils are lilac
4. Cytoplasmic granules of basophils are dark blue
   to black
5. Cytoplasmic granules of eosinophils are red to
   orange
6. The area between the cells should be clean and
   free of precipitated stain

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PERIPHERAL BLOOD SMEAR

• Peripheral smear examination
• Correct area of blood in which to evaluate
  cellular distribution and perform WBC estimate

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PERIPHERAL BLOOD SMEAR

• Peripheral smear examination
• Battlement pattern for performing a WBC
  differential count