Haematology Flashcards
True/false: PCV = Hct
True
PCV is the same as Haematocrit
PCV
Packed cell volume
The fraction of whole blood volume that consists of red blood cells
How is PCV calculated?
PCV = MCV x RBCcount/100
MCV
Mean corpuscular volume
The average volume of the red blood cells
MCH
Mean corpuscular haemoglobin
the average amount of haemoglobin per red blood cell
MCHC
Mean corpuscular haemoglobin concentration
the average concentration of haemoglobin in the cells relative to the size/volume of the cell
Anaemia
condition in which the capacity of the blood to transport oxygen is reduced. This is a clinical finding, not a diagnosis.
Can be caused by reduced number of circulating erythrocytes/reduced amount of haemoglobin per erythrocyte/both
Which 3 basic variables define whether an animal is anaemic or not?
- Total haemoglobin
- PCV
- RBC count
How do you characterise different types of anaemia?
- Macro/micro/normocytic - cell size - look at the MCV
- Hyper/hypo/normochromic - haemoglobin concentration - look at the MCHC
- Regenerative/non-regenerative - is the bone marrow producing reticulocytes? - look at reticulocyte count
Polycythaemia
a.k.a. erythrocytosis
having a high concentration of RBCs in the blood. Makes the blood thicker and can make flow sluggish.
Relative polycythaemia
apparent increase in RBC concentration due to a decrease in fluid in circulation e.g. due to dehydration, splenic contraction and release of RBCs due to adrenaline
Often there is also an increase in total protein and albumin.
Most common form of Polycythaemia.
Absolute polycythaemia
True increase in RBC concentration due to increased RBC production/release.
Can be primary e.g. bone marrow tumour that is over-producing RBCs.
Can be secondary e.g. chronic hypoxia of renal tissue due to heart disease (will see increased EPO with this).
