Chapter 3 Flashcards
Why is heparin unsuitable for haematologies?
It results in poor leucocyte staining
How does haemolysis affect a CBC?
^ MCHC and MCH
v RBC count and PCV
How does lipaemia affect the CBC?
^ Hgb, MCH, MCHC
How do Heinz bodies affect the CBC?
^ MCH, MCHC +/- increased WBC/reticulocytes (analyser dependent)
What can cause an elevated MCH/MCHC?
Usually spurious - lipaemia, haemolysis, Heinz bodies
Spherocytosis, eccentrocytosis, hyponatraemia
What are the affects of sample ageing on CBC?
Increased MCV and HCT, falsely low MCHC and MCH
WBC morphology deteriorates
How does autoagglutination affect the CBC?
Reduced RBC and hct, falsely high MCH, MCHC and MCV
What is the calculation for:
a) HCT?
b) MCHC?
c) MCH?
a) HCT = MCVxRBC
b) MCHC = Hb/HCT
c) MCH = Hb x 10/RBC
What is MCV? What does it indicate?
When can it be abnormal?
Mean corpuscular volume. Average size of RBCs
^ - regenerative anaemia, non-regenerative anaemia caused by myelodysplasia (ie FeLV), aged sample, autoagglutination
v - Iron deficiency
What is RDW? What does it indicate? When is it abnormal?
Red cell distribution width. Variability in erythrocyte size.
^ - regenerative anaemia and iron deficiency anaemia
*more sensitive indicator of altered RBC size than MCV
What is MCH? What does it indicate? How is it calculated?
Mean corpuscular haemoglobin
Weight of average RBC - doesn’t take volume into consideration
= Hb/RBC
What is poikilocytosis?
Altered cell shape
What is the normal lymphocyte:neutrophil ratio in the dog and cat?
D - 3.5:1
C - 2:1
How do cats/dogs eosinophils differ?
Cats granules always abundant and rod-shaped, dogs normally round, range from small amounts to abundant
Which breed of dog has different appearing eosinophils?
Greyhounds - non-staining granules gives vacuolated appearance
