Clinical Haematology Flashcards
Which type of collection tube should be used for blood sampling? Why?
EDTA blood tube
Where should blood samples be stored?
In the fridge - do not freeze (ruptures cells)
What can you assess via the circulating RBC mass?
Haematocrit and PCV%
How can you assess RBC morphology?
With a peripheral blood smear exam
How does flow cytometry work?
Individual cells passes through laser beam - cells are counted by interruption in light, cell size/complexity obtained by light scattered
What is impedance testing?
Passing cells in an isotonic solution between 2 electrodes - cells produce a change in electrical impedance that is proportional to the size of the cell
What is the packed cell volume?
Percentage of red cells in a volume of blood
What are the main parts of a blood smear? (3 part structure)
Base/head, monolayer, feathered edge
What type of leukocyte is this?
Neutrophil
- Defence against invading microorganisms (esp. bacteria)
- Increased with inflammation/infection/stress
What type of leukocytes are these?
Eosinophils (pink) and basophils (purple)
- defence against parasites (allergic response)
- basophils contain histamine
- known as granulocytes (along with neutrophils)
What type of leukocyte is this?
Lymphocyte
- Involved in cell-mediated immunity
- large nucleus, very little cytoplasm
- T and B cells
What type of leukocyte is this?
Monocyte
- Precursors to macrophages
- Antigen presentation to T cells
- Blob appearance, often have vacuoles
What does the suffix -philia/-cytosis mean?
Cell type increase in number
What does the suffix -penia mean?
Cell type decrease in number
What is the most dominant leukocyte cell type in dogs/cats/horses?
Neutrophils
What is the most dominant leukocyte cell type in healthy cattle and rodents?
Lymphocytes
Why can’t bird/reptile/amphibian blood counting be performed by analysers?
RBCs and thrombocytes (platelet equivalents) are nucleated so cannot be distinguished from RBCs
What are the clinical signs of anaemia?
- mucous membrane pallor
- lethargy
- exercise intolerance
- tachycardia/tachypnoea
- collapse
- icterus
What are the 3 traditional classifications for anaemia?
- RBC index (size/colour)
- Regenerative vs. non-regenerative
- Severity of the anaemia (nased on how low the haematocrit is)
What is regenerative anaemia?
Where bone marrow is responsive but cannot replace lost RBCs fast enough (usually seen in haemorrhage)
What is non-regenerative anaemia?
Where the bone marrow is unresponsive to cell loss
What factors are usually investigated for anaemia?
- PCV/HCT and Hb concentration
- RBC indexes
- Reticulocyte count (determine if regenerative)
- Blood smear for morphological evaluation of RBC
When might there be a high mean corpuscular volume (macrocytic RBCs)?
- Seen in bone marrow disorder
- seen in some types of poodle
- Common artefact in stored/old samples - RBCs swell up
What is a reticulocyte?
Immature precursor to a RBC
