Clinical Haematology 1 Flashcards
Which sampling tube should be used for haematology?
EDTA blood tube
Heparin can be used in some exotic species.
Respect the amount of blood required in tube.
Briefly describe the method for sampling for haematology.
Gently invert tube 10-20 times.
Prepare two fresh blood smears.
Fully and quickly dry the smears.
How should you store a haematology sample?
Store in fridge until running the sample.
Do not freeze.
Do not refrigerate the smears - leads to water artefact.
What seven ways can RBCs be evaluated?
Haematocrit, Packed Cell Volume (PCV), RBC count
Mean Corpuscular Volume (MCV), Mean Corpuscular Haemoglobin (MCH), Mean Corpuscular Haemoglobin Concentration (MCHC)
Peripheral Blood Smear exam
Briefly describe the two methods used by haematology analysers.
Flow cytometry:
Individual cells pass through laser beam, absorb/scatter light, interruptions in light = cell count, light scatter = size and internal complexity of cell. allows a differential count to be produced.
Impedance:
Individual cells pass in isotonic solution between two electrodes, cells are poor electrical conductors so when passed between electrodes, produce change in electrical impedance proportional to size of cell.
In a PCV, what colours can the plasma be and what does this indicate?
Clear/pale straw = normal
Bright yellow = icteric
Pink = haemolysed
Milky and turbid = lipaemic
What are we looking at in a blood smear?
RBCs - number, morphology, evidence of regeneration?
WBCs = number, type present, morphology
Platelets = number, morphology
Name the 6 sub-categories of leukocytes.
Neutrophils, eosinophils, basophils, lymphocytes, monocytes, platelets.
What does the suffix -philia mean?
Increase in number.
What does the suffix -cytosis mean?
Increase in number.
What does the suffix -penia mean?
Decrease in number.
How do we estimate a platelet number?
10 fields oil immersion in monolayer.
Count number of platelets, do an average.
Multiply by 15 or 20.
Estimated number (x10 9/L).
Normal = 15-30 platelets.
How can you tell the difference between regenerative and non-regenerative anaemia?
Non-regenerative = bone marrow not producing new RBCs, so all cells look the same.
Regenerative = weird shapes of RBCs.
How do agglutination and rouleux appear different?
Agglutination = appearance of grapes, 3D cluster, interferes with machine.
Rouleux = appearance of stacked coins, does not interfere with machine.
