Preparing a Blood Smear

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Preparing a Blood Smear
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Samples for Hematology

• Capillary blood and venous blood can be used for
  hematology tests.
• Capillary blood is beneficial if a small amount
  of blood is needed.
• Venous blood via venipuncture is beneficial if a
  larger amount of blood is needed for testing.
• Most hematology tests are run using blood
  collected with the anticoagulant,
  ethylenediaminetetraacetic acid, or EDTA for
  short.
• EDTA is the anticoagulant found in lavender top
  tubes.

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Samples for Hematology CBC

• A complete blood count or CBC is one of the most
• commonly ordered test in the hematology
  department.
• When running a CBC there are several separate
  tests run.
• Tests included in a CBC are.
• Red Blood Cell Count (RBCs)
• White Blood Cell Count (WBCs)
• Hemoglobin (Hgb)
• Hematocrit (Hct)
• Mean Corpuscular Volume (MCV)
• Mean Corpuscular Hemoglobin (MCH)
• Mean Corpuscular Hemoglobin Concentration (MCHC)
• Differential count (Diff)
• Platelet Count (PLTs)
• Blood Cell Morphology

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Blood Smears

• A CBC also includes an examination of a blood
  smear if there are issues with the CBC.
• A smear of blood is made and then stained and
  examined by the laboratory personnel.
• Stained slides can be read manually (by a person)
  and sometimes by a machine.
• Ultimately a person must review the slides before
  results are reported.
• Blood smears are checked for types of WBCs,
  shapes of RBCs, and the presence of platelets.
• Morphology ? the structure and shape of cells
• The morphology off all cells are reviewed.

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Preparing a Blood Smear

• Equipment needed to perform a blood smear
  include..
• Clean slides (prewashed or cleaned)
• Capillary supplies or Venipuncture supplies
• Fresh tube of blood

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Preparing a Blood Smear

• Making a blood smear
• Place a small drop of blood ½
• inch from the frosted end of a
• slide.
• The end of a second slide is
• used to spread the blood drop
• out on the first slide.
• Pull the end of the slide
• through the blood drop toward
• you and then push in the
• opposite direction forcing the
• blood in your direction.

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Preparing a Blood Smear

• Making a blood smear
• A good smear should..
• cover around ¾ of the slide
• have a feathered edge
• move from thick to thin
• cells should be evenly distributed
• RBCs should not overlap
• Factors that affect the smear include..
• blood drop size
• angle of the slide used to spread
• speed of the procedure
• Making an acceptable slide takes lots of
  practice!

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Preparing a Blood Smear

• Staining the blood smear
• The smear should be stained as soon as
• possible after the slide dries.
• If the slide cannot be stained
• immediately, it can be immersed in
• methanol (fixed) and stained later.
• Blood smears are most commonly
• stained with Wrights stain.
• Wrights stain can come in many forms
• including one dip stains, two stains,
• multiple stains, or automated staining
• of slides.

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Reading a Blood Smear

• Reading a Blood Smear
• The elements you will be looking for
• in a stained blood smear are RBCs,
• WBCs, and PLTs.
• The WBCs will be counted according
• to their type.
• RBCs and PLTs are easier to identify
• than WBCs.
• To categorize the different types of
• WBCs, look for the following
• things..
• Size in comparison to the RBCs
• Nuclear shape and staining
• Cytoplasm makeup and staining

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Reading a Blood Smear

• Reading a Blood Smear
• You count each WBC in each category
• until you reach a total of 100 cells.
• The number you got for each type of cell
• divided by 100 will give you the
• percentage each type of cell is found in
• each sample.
• For example if you counted..
• 55 neutrophils 55 of WBCs were neutrophils
• 30 lymphocytes 30 of WBCs were lymphocytes
• 10 monocytes 10 of WBCs were monocytes
• 3 eosinophils 3 of WBCS were eosinophils
• 2 basophils 2 of WBCS were basophils