LAB 3 & 4

• A properly prepared blood smear is utilized for platelet estimation and for the observation of any abnormal platelet size and distribution
• The film is 2/3 or 3/4 the length of the slide
• < length = cells are not evenly distributed (cells are concentrated in the middle)
• The film is finger-shaped, very slightly rounded at the feather edge, not bullet-shaped; this provides the widest area for examination
• Bullet tail = big cells are concentrated in the tail
• The lateral edges of the film are visible
• Has margination = to not push cells outward = observation of abnormal cells and even distribution
• The film is smooth without irregularities holes, or streaks
• Holes = caused by dirty and wet slides
• Wave-like formation = held up too early, still wet
• When the slide is held up to the light, the thin portion (feather edge) of the film has a “rainbow" appearance
• Thick-to-thin transition = even distribution
• The whole drop of blood is picked up and spread
• Thick only = cells are very congested
• Methanol: fixative
• Eosin: acidic (-) stain

  • Stains eosinophilic structures (cytoplasm, hemoglobin and eosinophil granules)
• Methylene blue: basic (+) stain

  • Stains basophilic structures (DNA, RNA, and nucleus)
• Wash Water (Distilled Water): washed off stain residue
• Two-Glass Slide Method: Wedge Slide or Push Smear
• Slides (75mm length x 25mm width)
• Uses 2 slides: stationary slide and spreader slide
• Angle: 30 - 45 degree
• Drop of blood: 2 - 3 mm in diameter
• Four factors that affect the consistency of smear: Pressure, Angle, Speed, Size of blood
• Decrease pressure = thick

  Increase pressure = thin
• Increase angle = thick and short

  Decrease angle = thin and long
• Increase speed = thick

  Decrease speed = thin
• Increase size of blood = thick

  Decrease size of blood = thin
• Decrease angle = thin and long = high hematocrit (viscous blood)

  Increase angle = thick and short = low hematocrit (less viscous)
• 10x Low Power Objective Examination

  • Transitioning
  • Fibrin strand
  • WBC distribution
• 40x High Dry Objective Examination

  • Rouleaux formation
  • WBC estimate
• 100x Oil Immersion Objective Examination

  • Platelet estimate
  • Blood cell morphology evaluation
• 10x Low Power Objective Examination

  • To look for the transitioning of the distribution of cells (rouleaux formation to well distributed area)
• 10x Low Power Objective Examination

  • Look for the fibrin strand = presence of clotting = low RBC and consumed platelets = reject
• 10x Low Power Objective Examination

  • WBC distribution should be checked (not concentrated at one edge, but must be concentrated throughout the tail)
• 40x High Dry Objective Examination

  • Evaluate the rouleaux formation (stock of coin) – do not count here, go to well-distributed area
• 40x High Dry Objective Examination

  • WBC estimate
• 100x Oil Immersion Objective Examination

  • Platelet estimate
• 100x Oil Immersion Objective Examination

  • Blood cell morphology evaluation (such as their size and shape)
• WHERE TO PERFORM PLATELET ESTIMATE?

  • Count in the FREE AREA in which RBCs are separated from each other (minimal overlapping of RBCs)