RBC Parameters Flashcards
What are we assessing in Haematology in terms of RBCs?
Red cell mass
Evidence of effective erythropoiesis
Cell size and variation
Haemoglobinisation (colour)
Shapes and inclusions
How do we assess red cell mass?
PCV/Hct
RBCC
Hgb
How do we assess erythropoiesis?
Size/colour
MCV
MCHC
Reticulocyte count
How do we assess cell size and variation?
MCV
RDW
How do we assess haemoglobinisation?
MCHC
‘Rule of Three’
Hct = ~Hgb x3
Why might PCV be incorrect?
RBC’s miscounted
Mistaken for platelets
Aggregated into pairs and triplets
MCV misleading
Cell shrinkage or swelling
Transport, tube filling
Osmotic effects in machine
MCHC meaning
Mean corpuscular haemoglobin concentration
MCV meaning
Mean corpuscular volume
Classification of anaemia
MCV - ‘cytic’
MCHC - ‘chromic’
Normocytic normochromic
○ Often anaemia of illness or pre-regenerative or occasionally non-regenerative
Macrocytic hypochromic
○ Classic highly regenerative
○ Sometimes could just be cell swelling of transport
Microcytic hypochromic
○ Classic iron deficiency
Chronic external blood loss
○ Without anaemia
Portosystemic shunts
Polycythaemia
Increase in PCV, Hgb concentration and RBC count
Relative polycythaemia
Apparent increase in RBC due to decrease in fluid circulation
Dehydration is a common cause
Absolute polycythaemia
True increase in RBC ,ass due t increased production
Primary Polycythaemia (polycythaemia vera)
Rare myeloproliferative disorder
Abnormal response of RBC precursors
Normal EPO levels
Secondary Polycythaemia
Chronic tissue hypoxia of renal tissues (low arterial pO2) due to:
Heart/lung diseases
High altitude
Thrombosis
Constriction of renal vessels
Renal tumour or cysts [↑intra-capsular pressure]
Increased EPO
Reticulocytes
Immature erythrocytes
Used to evaluate erythropoiesis
Differentiated between regenerative and non-regenerative anaemia
Species variation in reticulocytes
Dogs:
○ Low number of reticulocytes
Cats:
○ Low number of reticulocytes
○ Cats have two morphological types of reticulocytes
Ruminants and horses:
○ Virtually no reticulocytes in normal blood
