CBC Evaluation

Question 1

What cells are classified as granulocytes by hematology analyzers?

Answer 1

Neutrophils, basophils, eosinophils

Question 2

What is the difference between impedance and flow cytometer analyzer technology?

Answer 2

Impedance: sorts cells by size only

Flow cytometry: sorts cells by size, complexity, staining

Question 3

What are rouleaux and agglutination and why do these occur?

Answer 3

Rouleaux: coin-stacking of RBCs due to increased fibrinogen or protein. Can be normal in cats, large animals.

Agglutination: Clumping of RBCs.

Differentiate via saline dispersion test

Question 4

What is leukergy? What is its significance?

Answer 4

Aggregation of WBCs

Non-specific, seen with many inflammatory/infectious diseases

Can cause blood machines to report leukopenia

Question 5

How are canine erythrocytes morphologically different (i.e. appear different through the microscope) from other species?

Answer 5

Central pallor

Question 6

What does increased polychromasia indicate? What is responsible for this alteration in color?

Answer 6

Reticulocytes

Retained RNA

Question 7

Benign or artifactual types of poikilocytosis and their mechanism of formation?

Answer 7

Echinocytes (crenation); EDTA tubes filled insufficiently

Dacryocyte; incorrect slide preparation

Stomatocyte; thick areas of blood smear

Question 8

What does hypochromasia indicate? What is responsible for this alteration in color?

Answer 8

Decreased hemoglobin

Question 9

Physiologic and pathologic RBC inclusions with their mechanism of formation?

Answer 9

Howell-Jolly bodies: retained nuclear fragment

Basophilic stippling: aggregates of ribosomes

Heinz bodies: denatured hemoglobin

Pappenheimer (siderotic) bodies: iron granules

Retractile (water) mark: slow drying or water stain

Stain precipitate

Canine distemper viral inclusion

Question 10

Indications and procedure for performing a corrected total leukocyte count?

Answer 10

Exotic patients (nRBC) or not performing full CBC

tWBC machine x 100(100 + (nRBC/ 100 WBC))

Question 11

Differentials for increased nRBCs?

Answer 11

Appropriate:
Regenerative anemia
Physiologic (breed)

Inappropriate:
Lead poisoning
Heat stroke
Bone marrow injury
Dyserythropoeisis 
Abnormal splenic function

Question 12

How do you perform a platelet slide estimate in a dog or cat?

Answer 12

Avg #/10 HPF x 15-20,000

Question 13

How do you perform a leukocyte slide estimate and differential?

Answer 13

Slide estimate:
Avg #/ 10 HPF x (objective)^2

Differential:
Count at least 100 cells

Question 14

Are Döhle bodies always considered a sign of toxicity, why or why not?

Answer 14

Small, basophilic aggregates of RNA in cytoplasm of neuts

Not always, can be normal in cat

Question 15

Pathologic types of poikilocytosis and their mechanism of formation?

Answer 15

Basically all of them

Caused by changes in RBC membrane, oxidative damage, etc.