Card Set Information
Describe how to perform a bone marrow differential (simple)
500 nucleated cells are counted (NRBCs and WBCs) are counted in successive fields
Cells without nuclei are not included
What is the appropriate angle for the spreader slide technique, and what happens on either side?
30-45 degrees is optimal
>45 degrees results in a thick slide
<30 degrees results in a thin slide
What is the normal stain used in a differential or count? What "type" of stain is it? What are the primary ingredients? What is the primary reaction?
Includes methylene blue, Eosin B or Y, methyl alcohol, phosphate buffer (pH 6.4-6.7)
Acid-base affinity induces stain
What is the procedure for a Wright stain?
Add methylene blue/eosin stain mixture for 3 minutes
Add phosphate buffer to stain and mix
Allow both to remain on smear for 5 min
Rinse slide with water
What aspects of the cells will stain in various colors in a Wright stain? Why?
Acid substances have an affinity for the basic methylene blue (DNA, RNA)
Basic substances have an affinity for the acidic eosin and stain red (hemoglobin, various enzymes in cytoplasm)
Describe how to perform an examination of peripheral blood film (in detail)
Low power scan (10x)
: evaluate staining quality
evaluate distribution of cells (clumping? abnormalities?)
determine optimal examination area
High power scan (40x)
: estimate WBC count
count WBCs in 10 consecutive fields and determine the average per field
2-4 = 4,000-7,000 WBC/μL
4-6 = 7,000-10,000 WBC/μL
6-10 = 10,000-13,000 WBC/μL
10-20 = 13,000-18,000 WBC/μL
: evaluate RBC morphology (anisocytosis, poikilocytosis, hypochromia, polychromasia, RBC inclusions)
Estimate platelet count
count platelets in 10 successive fields and determine the average per field
multiply the average by 20,000 (or 15,000 if automated slide) to determine the #platelets/μL
normal platelets (130-000-400,000)
WBC differential count
Count and ID all WBCs (including immature) in successive fields until 100 have been counted
Also count (but don't ID) NRBCs
If >10 NRBCs are found then count needs to be corrected
What are the normal values for a WBC differential?