Haematology - WBCs and platelets

Question 1

What are the functions of each WBC?

Answer 1

Neutrophil and monocyte - phagocytosis (innate immunity)
Lymphocyte - able to recognise antigens (T and B cells, adaptive immunity)
Eosinophils and basophils - defines against parasites and allergies

Question 2

Which cells are polymorphonuclear/granulocytes?

Answer 2

Neutrophil - granules not visible with stains
Eosinophil
Basophil
All the phils

Question 3

Which are the largest and smallest WBCs?

Answer 3

Largest - monocyte

Smallest - lymphocyte

Question 4

What are immature neutrophils called?

Answer 4

Band cells

Question 5

How many WBCs are seen in a 10X field to presume leucocytosis or leucocytopenia?

Answer 5

Leucocytosis - >50

Leucopenia - <18

Question 6

The automated analyser total for WBC is usually accurate. When might it be inaccurate and require manual counting?

Answer 6

Many nucleated RBCs (detects as WBCs)

WBC clumped in a clot (still inaccurate if manual count)

Question 7

Where should a differential WBC count be performed on a blood spear? What pattern is used?

Answer 7

Monocyte layer - feathered edge cells not intact

Battlement pattern - make sure to calculate full blood count as may seem normal until scaled up

Question 8

What abnormal WBCs are seen with acute inflammation?

Answer 8

Neutrophiliia
Band neutrophils
Lymphopenia

Question 9

What abnormal WBCs are seen with chronic inflammation?

Answer 9

Neutrophilia

Monocytosis

Question 10

What can cause neutropenia?

Answer 10

Severe inflammation - sepsis, endotoxaemia, tumour necrosis, bone marrow disease
Also cows with acute inflammation

Question 11

What is a stress leucogram?

Answer 11

Stress or prolonged steroids in blood causes:
L - lymphocytopenia
E - eosinopenia
M - monocytosis
N - neutrophilia
(LEMoN)

Question 12

What is left shift?

Answer 12

Increased number of immature neutrophils (band cells or earlier) released from bone marrow

Question 13

What causes left shift?

Answer 13

Severe, acute inflammation

Question 14

What may marked lymphocytosis indicate?

Answer 14

Leukaemia

Question 15

What causes eosinophilia and basophilia?

Answer 15

Parasitic disease
Allergy
Type I hypersensitivity

Question 16

What is toxic change? What does it suggest?

Answer 16

Increased blue colour of WBCs

Intense myelopoiesis stimulation - don’t have time to mature

Question 17

Describe megakaryocytes size and nuclear

Answer 17

LARGE

Lobated nuclei

Question 18

What are giant platelets? What do they suggest?

Answer 18

Platelets larger than RBCs

Increased thrombopoiesis

Question 19

Platelet clumps are common in feline and bovine blood samples. Why?

Answer 19

Slow/poor venepuncture,
Inadequate mixing with anti-coagulant
Hyperactive platelet

Question 20

What can cause thrombocytopenia?

Answer 20

Increased destruction - immune-mediated thrombocytopenia (autoimmune or idiopathic)
Increased consumption
Decreased production
Redistribution

Question 21

What could cause redistribution of platelets and thrombocytopenia?

Answer 21

Splenic torsion, splenomegaly

Question 22

What clinical signs may be seen with severe thrombocytopenia?

Answer 22

Petechia, purpura, ecchymoses
Epistaxis (nose bleed)
Melaena and haematochezia
Haematouria

Question 23

What does moderate and severe thrombocytosis indicate?

Answer 23

Moderate - no clinical significance, common

Severe- chronic bleeding, inflammation, iron deficiency