Abnormalities of the Leukon Flashcards Preview

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Flashcards in Abnormalities of the Leukon Deck (77)
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1

What are the two methods of measuring leukocytes through a machine?

Impedance/optical
Quantitative buffy coat

2

How does an impedence/optical machine calculate WBC numbers?

Lyse RBC and stream nucleated cells through a channel where electrical impedance or optical deflection is noted

3

What are the pros and cons of using impedence/optical machines to measure WBCs?

Accurate for total numbers
If there is regenerative anaemia present not accurate as nucleated RBCs are counted as well

4

How is a quantitative buffy coat used to measure WBC numbers?

Scans a spun down large PCV tube and related fractions to where cell types settle

5

In what order from bottom to top do WBCs settle in the buffy coat?

Basophils, mast cells, eosinophils, monocytes, lymphocytes, platelets

6

What are the disadvantages of using quantitative buffy coat analysis to calculate WBC numbers?

Problems with abnormal cells/platelet enumeration
Differentials poorly performed

7

What are some manual methods used to calculated WBC numbers?

Chamber counts/unopette systems used for exotics
Blood smear estimates from a monolayer assuming there is no clotting or clumping

8

How is a blood smear estimate of WBC numbers calculated?

Number of leukocytes in the monolayer of a 100x field counted then divided by four which correlates roughly to WBC x10^9/L
Average at least 10 fields to minimise variation across smear

9

What does total WBC concentration include?

All neutrophils, lymphocytes, monocytes, eosinophils and basophils

10

How are specific leukocyte numbers calculated?

Count 100 cells per 10x10^9/L total WBCs then times percentage of cells by concentration of WBCs to get absolute concentration

11

How do you compare specific numbers to absolute concentration of WBCs?

Percentage of specific leukocytes can be compared directly but absolute concentration needs to be compared to WBC concentration for context

12

What factors influence total leukocyte numbers?

Dynamic equilibrium
Balance between peripheral demand and the ability of bone marrow to supply adequate replacements
Position of the leukocyte (marginated/circulating)
Availability for sampling

13

What are the kinetics of neutrophils in a healthy animal?

Each stage of production of a neutrophil takes about a da and remain in the blood for between 30 minutes-6hours

14

What is the self-renewal stem cell for neutrophils

CFU-G

15

What cells make up the ProNP?

Myeloblasts, progranulocytes and myelocytes

16

What stimulates the mitotic pool?

IL-1, IL-3, IL-6, GM-CSF, G-CSF

17

When does apoptosis occur in health to prevent overproduction?

Myelocyte stage

18

Which cells make up the MatNP?

metamyelocytes, band neutrophils and segmented neutrophils

19

What is the ratio of MatNP to ProNP?

4-6

20

What is the SNP?

Storage neutrophil pool made up of sub-pool of MatNP with cells ready to be released into marrow sinusoids

21

What species differences are there in SNP?

Dogs and cats have good storage but horses don't

22

What is the CNP?

Circulating neutrophil pool that is samples in blood collection

23

What is the MNP?

Marginated neutrophil pool which are the cells ready to exit the circulation and migrate into the tissues

24

What is the TNP?

Tissue neutrophil pool

25

What is the CNP:MNP ratio?

Near 1 but can be 3 in cats

26

What changes occur in left shift of neutrophils?

More band neutrophils, may see toxic changes, cytoplasmic foaminess and basophilia, Dohle bodies, giant neutrophils, vaculolation and toxic granules

27

What causes changes see in left shift of neutrophils?

Accelerated production

28

What is regenerative left shift of neutrophils?

Production meets demand and more resulting in neutrophilia and more segmented cells than band

29

What is a degenerative left shift of neutrophils?

Production doesn't keep up with demand resulting in neutropenia and bands in the circulation in greater numbers than segmented

30

Why are large animals more prone to degenerative left shift?

They have less storage