Haematology - Erythrocyte morphology Flashcards Preview

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Flashcards in Haematology - Erythrocyte morphology Deck (14)
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Name some commonly seen morphological changes



Hypo and polychromasia

Schistocytes -haemolysis

Intracellular inclusions


Rouleux formation


Describe canine RBC morphology

circular relatively uniform, large, biconcave (like a Trebor mint) discs with a central pallor.

mature RBC are anucleated


Describe feline RBC morphology

circular, but smaller and more variable in size and shape than canine, with little or no central pallor.

mature RBC are anucleated


Describe crenation

This occurs when there is a disruption in the cells ability to maintain its isotonic state e.g. exposure to a hypertonic solution (drug therapy), electrolyte imbalances etc.

Water leaves the cell by osmosis causing the cell to take on a distorted, shrivelled and spiky appearance.

No real clinical significance

Commonly caused as a result of inappropriate blood sampling, handling, storage and testing techniques e.g. use of aged blood sample, EDTA tubes that have not been sufficiently filled etc.


Describe a schistocyte

This is a fragmented RBC that is a result of cell haemolysis (bursting of the cells).

Seen in patients with haemolytic anaemia, burns, uraemia.

May have no clinical significance and caused as a result of inappropriate blood sampling, handling, storage and testing techniques.


Describe anisocytosis

An abnormal variation in the size of red blood cells.

Commonly seen in severely anaemic patients.


Describe hypochromasia

An increase in central pallor, greater than ½ cell has central pallor.

Caused by a deficiency in the production of haemoglobin as a result of iron deficiency caused by chronic haemorrhage.


Describe polychromasia

An abnormally high number of immature red blood cells are found within the blood stream.

These are large, round RBC’s that are prematurely released from the bone marrow during formation (reticulocytes).

They commonly appear densely stained a blue or lilac colour from uptake of eosin stain, rather than the pink/red colour of a mature cell.

Causes can be related to anaemia commonly as a result of bone marrow damage e.g. osteosarcoma.


Describe Autoagglutination

Clumping of red blood cells (bunches of grapes).

This is as a consequence of the presence of antibodies (IgM) on the surface of the blood cell.

Seen to occur in immune mediated haemolytic anaemia (cold agglutination) as a result of lymphoid tumors and mycoplasma. This condition can be confirmed by use of a Direct Coombs test


Describe the Rouleaux Formation

Not to be confused with agglutination. The RBC’s in Rouleaux formation present in a very distinctive “stacking” arrangement (like a pile of coins).

This is caused by an increase in the number of plasma proteins within the blood, causing the flat round surface of the cells to stick to each other.

Can be clinically insignificant in some cats and horses

Commonly seen in cases with infection, inflammatory conditions, myeloma, and other types of neoplasia.


Describe intracellular inclusion

Howell-Jolly Bodies

Circulating RBC’s with intra cellular remnants of a basophilic DNA nuclei.

Seen in animals with absence of spleen, splenic disease, and regenerative anaemia.


Describe Heinz bodies

Formed from denatured protein

Possibly as a result of toxicity


Describe babesia

Parasite transmitted by ticks

Intracellular inclusion

Detected using Romanowsky stain


Describe patelets

Round/spindle shaped fragments of cytoplasm with no nucleus

Used in clot formation