Flashcards in Abnormalities of the Leukon Deck (77)
What are the two methods of measuring leukocytes through a machine?
Quantitative buffy coat
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
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
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
In what order from bottom to top do WBCs settle in the buffy coat?
Basophils, mast cells, eosinophils, monocytes, lymphocytes, platelets
What are the disadvantages of using quantitative buffy coat analysis to calculate WBC numbers?
Problems with abnormal cells/platelet enumeration
Differentials poorly performed
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
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
What does total WBC concentration include?
All neutrophils, lymphocytes, monocytes, eosinophils and basophils
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
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
What factors influence total leukocyte numbers?
Balance between peripheral demand and the ability of bone marrow to supply adequate replacements
Position of the leukocyte (marginated/circulating)
Availability for sampling
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
What is the self-renewal stem cell for neutrophils
What cells make up the ProNP?
Myeloblasts, progranulocytes and myelocytes
What stimulates the mitotic pool?
IL-1, IL-3, IL-6, GM-CSF, G-CSF
When does apoptosis occur in health to prevent overproduction?
Which cells make up the MatNP?
metamyelocytes, band neutrophils and segmented neutrophils
What is the ratio of MatNP to ProNP?
What is the SNP?
Storage neutrophil pool made up of sub-pool of MatNP with cells ready to be released into marrow sinusoids
What species differences are there in SNP?
Dogs and cats have good storage but horses don't
What is the CNP?
Circulating neutrophil pool that is samples in blood collection
What is the MNP?
Marginated neutrophil pool which are the cells ready to exit the circulation and migrate into the tissues
What is the TNP?
Tissue neutrophil pool
What is the CNP:MNP ratio?
Near 1 but can be 3 in cats
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
What causes changes see in left shift of neutrophils?
What is regenerative left shift of neutrophils?
Production meets demand and more resulting in neutrophilia and more segmented cells than band
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