Blood Smears Flashcards
Why do we do blood smears?
RBC and WBC morphology (what does it look like) Platelet count (clotting ability) WBC differential (relative values) Absolute values
What does the absolute value gives us?
The number of each WBC per microliter of blood
What is the importance of blood smears?
Cell morphology Classify anemia WBC differential Find abnormalities automated cell counter QC for automated cell counter
What are the three parts of the stain?
Fixative
Eosin component
Methylene blue component
Fixative
95% methanol
takes out all of the moisture
Eosin component
Stains hemoglobin and eosinophil granules
Methylene blue component
Stains the nucleus
How to evaluate a blood smear
4x-focus slide
10x-scan the slide for platelet clumping, microfilaria
40x-focus on monolayer, look at overall cellularity
100x-cell evaluation and counting
What does a blood smear that is too thick look like under the microscope?
RBC clumped together
WBC smooshed with RBC
What does a blood smear that is too thin look like under the microscope?
Big gaps of RBCs
What does a blood smear that is just right look like under the microscope?
monolayer,
one cell layer thick
not clumped
Why do you develop a system to look at a slide under a microscope?
Don’t count the same WBC twice
Can easily come back to it
What are the two patterns to look at a slide under a microscope?
Battlement pattern
Wandering pattern
What are the two methods to quantify morphologic changes on a blood smear?
- Slight, Moderate, Marked
2. Scale of 1+, 2+, 3+, 4+ to indicate relative percentages of cells with changes
Slight, moderate, marked
Slight=10%
Moderate=25%
Marked=50%
Scale method
1+=5% to 10% 2+= 10% to 25% 3+= approximately 50% 4+= more than 75% Used more in urine and ear cytology
What 5 things are you looking for during an erythrocyte evaluation
Cell arrangement RBC size RBC color RBC shape Inclusions/Parasites
What do you evaluate thrombocytes for?
Distribution, morphology, inclusions and number
What is a normal number of thrombocytes?
160,000-625,000
7-10/ oif
Thrombocytopenia
low platelet count
if the count is lower than 100,000 it is usually significnt
What thrombocyte count indicates bleeding?
20,000-50,000
What may affect RBC counts on an automated anaylzer?
Proplatelets
Very recently pinched off from megakaryocyte
What species do the thrombocytes not stain as intensely
Horses
What species see a often high number of thrombocytes?
Rodents
