Leukocytes

How to manually count leukocytes with light microscope

Calculate average WBCs on 5 low power (10x) fields

multiply by 1000 and divide by 4

= within ± 20% actual WBC number

What is this cell? What are its activity features

Neutrophil. Most common WBC

Rapid production following infection. Have a short half life so high numbers indicate active infection

Produce pus

4 differentials for neutrophilia

Inflammation

Infection

Excitement

Stress

What are these cells? What are their activity features

Lymphocytes

Adaptive immune response, take longer than neutrophils to come to site of inflammation

T-cells and B-cells. Cant be differentiated without IHC

What is this cell?

Monocyte

Larger than band neutrophils with less uniform nucleus

What are these cells? What do they indicate?

Eosinophils

Allergic and parasitic infections

Differentials for neutropoenia (3), and example causes

Acute severe infection

Endotoxaemia

Bone marrow inhibition/disease (chemotherapy)

Canine parvovirus can cause all 3 = severe neutropoenia

What are the 4 changes seen in a stress leukogram

Neutrophilia (mature)

Lymphopoenia

Monocytosis

Eosinopenia

3 changes seen in an inflammatory leukogram

Neutrophilia (immature)

Lymphopenia

Monocytosis

3 changes seen in a reverse stress leukogram

Neutropoenia

Lymphocytosis

Eosinophilia

4 differentials for eosinophilia

Allergy

Parasitic infections

Hyperthyroidism

Addisons/hypoadrenocorticism

Differential of marked lymphocytosis in horse and dog

Leukaemia