3: Haematology 1 Flashcards
Which tube is preferred for haematology?
EDTA
Why are citrate tubes used in cats?
Reduces platelet clumping
Why is heparin used for exotics?
Can’t get much blood and can also be used for biochemistry
What’s a problem with using heparin?
Poor staining of WBCs on smears
What are three problems if an EDTA tube is underfilled?
Alters RBC size/morphology, reduced PCV, dilutes sample if the EDTA is liquid
What happens if biochemistry tube gets contaminated with EDTA?
Increased K and decreased Ca
Normal dog PCV?
37-55%
Normal cat PCV?
26-45%
What is plasma protein concentration measured in?
g/L
What three things can cause false plasma protein conc increases
Lipaemia, urea, glucose
What process is occuring if PCV is normal and plasma protein is high?
High serum globulin from inflammation, infection, myeloma or some B cell lymphomas
What are the two types of RBC analysers?
Impedence and flow
How do impedence analysers work?
Pass cells through an electrical current and larger cell creates a larger pulse
How do you calculate haematocrit?
RBC x MCV / 1000
Within what % of the PCV should the HCT be?
2-3%
If PCT and HCT are different, which do you believe?
PCV
How do you calculate MCH?
HGB x 10 / RBC
Which three cell-specific lysing solutions are used in an impedence analyser?
Granulocytes, lymphocyte, monocyte
What can band neutrophils be accidentally classed as?
Monocytes
What can nRBCs be accidentally classed as?
Lymphocytes
How do impedence analysers differentiate platelet vs RBC?
Based on size
Why do impedence analysers confuse platelets vs RBCs in cats?
Large platelets, small RBCs
Why do impedence analysers confuse platelets vs RBCs in CKCS?
Few, large, platelets
How do flow analysers work?
Pass cells through laser beam and a low scatter angle is a larger cells and higher angle is a granular complex cells
What is the advantages of a flow analyser?
Better at RBCs vs platelets, get 4 part WBC differential, can tell neutrophil and eosinophil apart, can identify and count reticulocytes
What do flow analysers get confused between?
Neutrophil and monocyte
How does a QBC analyser work?
Centrifugal force separates RBCS, granulocytes, agranulocytes, platelet layers and thickness = concentration
When QBC be inaccurate?
If cell sizes are abnormal
Why is QBC good for CKCS?
Calculates platelet mass (placecrit) rather than cell count
What do QBC analysers have fluorescent markers on tubes for?
DNA, RNA, lipoproteins
Which cell types does the myeloid precursor become?
Platelets, RBCs, WBCs (except lymphoid cells)
In which bones does bone marrow haematopoiesis occur?
Flat and proximal long bones
Where can you aspirate bone marrow from?
Iliac crest, femur, proximal humerus
Which kind of animals have extra-medullary haematopoiesis?
Old
Where does extra-medullary haematopoiesis occur?
Spleen, liver, lymph nodes
Around which cells are erythrocytes produced in the bone marrow?
Macrophage nurse cells
Which cells produce EPO?
Peritubular interstitial
Why does pulmonary disease cause erythropoiesis?
EPO produced in response to hypoxia
How many mitoses does a rubriblast undergo?
Multiple
What do the cells produced by rubriblast mitosis look like?
More, smaller
At what stage is the nucleus extruded to form reticulocytes?
Metarubricyte
In which species is the nucleus not extruded?
Reptiles or birds
How does iron deficiency cause microcytosis?
Hb regulates cells division and less Hb = more division
After how long are reticulocytes released and mature?
24-48 hours
What do reticulocytes look like on blood film?
Polychromatophils due to ribosomes
Why are reticulocytes rare in cows or horses on blood films?
Mature before release
Which stain do you use for reticulocytes?
Methylene blue
Which kinds of reticulocytes do cats have?
Aggregate and punctate
Which kind of reticulocytes do most species have?
Aggregate
What do punctate reticulocytes look like?
Not polychromatic and can’t be differentiated on blood smear
What are aggregate reticulocytes released from bone marrow as?
Polychromatophils
What evidence of regeneration do aggregate reticulocytes show?
Recent
What happens to aggregate reticulocytes?
Become punctate
