RBC morphology Flashcards
Morphology of normal mammalian erythrocytes
Varies among species
Canine- biconcave disc shape with a distinct area of central pallor
Feline- round with little or no central pallor
Avian, reptiles, amphibians, and fish all have nucleated RBCs
Camellidae family have elliptical RBCs
Procedure for reporting RBC morphology
Under high dry (40x) find an appropriate monolayer area to evaluate (where you would perform your differential count)
Look for agglutination, reuleaux, parasites or an abnormal sized monolayer
Under oil immersion examine the erythrocytes for variations in size, shape, colour and the presence of inclusions
Morphological characteristics Categorized according to
Cell arrangement
Cell size
Cell colour
Cell shae
The presence of structures on or in the erythrocyte
Erythrocyte arrangement on blood smears: Rouleaux is
Is when the red blood cells appear in linear stack(like stocked coins)
A normal finding in horse
Cats and pigs will normally have a slight rouleaux
It can be an artefact if the blood has been stored too long before the smear is made, or it was refrigerated before a blood film was made
May be seen with increased total protein levels in the blood
Must be reported
Exception: rouleaux is not reported in the horse and is only reported in cats if it is 3+
Accompanied by an increase in erythrocyte sedimentation rate
Agglutination is and looks like
Results in irregular, spherical clumps of cells
In early stages, it may appear as increased rouleaux with some cells appearing to be connected by long, thin extensions of the RBCs cytoplasm
As it progresses, the cells will take on a muddy brown colour and “melted together” appearance
Occurs due to a reaction between antibodies (usually) and the antigens present on the surface of the RBCs
To differentiate rouleaux formation from true agglutination the following test can be performed
Mix a small amount of blood at a ratio of 50;50 with warm (or room temp) isotonic saline
Make a smear and stain as usual
If the formation disappears, it is due to a high total protein concern of the plasma
If agglutination is still visible, there is antibody involvement
Normocytic means
Cells of a normal size
Macrocytic means
Larger then a normal size cell
Microcytic means
Smaller then normal cells
Ansicytosis means
Variation in size
Common in cattle and rates therefore not reported
Macrocytic erythrocytes look like
Large in diameter, generally twice the size as normal
Dogs: erythrocytes only need to be slightly larger than normal to be classified as macrocytes
The cells have an increased MCV
Microcytic erythrocytes looks like
Smaller in diameter than normal
Often accompanied by hypochromasia
MCV will be lower than normal
RBCs should be what colour
RBCs are said to be normochromic when there are no abnormalities in cell colour
MCH (mean corpuscular hemoglobin) in normal
MCHC( mean corpuscular hemoglobin concentration) is normal
Polychromasia means
refers to a cell being darker in colour than normal
How to stain in order to see colour
Wright’s stain: appear as macrocytic, blue tinged red cells
They are immature RBCs
Blue staining is due to the presence of organelles within the cells
Polychromasia is important why and usually accompanied by
AN EXTREMELY IMPORTANT ELEMENT OF A PATIENT’S BLOOD PROFILE
Usually accompanied by
An increased number of nucleated RNCs
Hypersegmented neutrophils
Howell Jolly bodies
What does polychromasia indicate
Horses will release macrocytic RBCs that are not polychromatic
An increase indicates regenerative anemia→ good prognosis
A lack of macrocytic cells indicates a non-regenerative anemia→ poor prognosis
Hypochromasia look like
Cells are more pale in colour than normal
Increased central pallor
Due to a decreased hemoglobin concentration within the cell
Macrocytic RBCs can appear to be hypochromic because of enlarged cell size
Hypochromasia is caused by
Due to a decreased hemoglobin concentration within the cell
Can be due to poor smear technique
-Have what looks like a punched out center
What can hypochromasia indicate
Micrystosis often accompanies hypochromasia
-Iron deficiency
Hyperchromasia is
Cells that are stained darker than normal
RBC have a fixed maximum so versaturation is not possible
Hyperchromasia is usually seen spherocytes or microcytic cells
Erythrocyte shape can indicate
When describing the RBC shape, be as specific as possible
Certain shapes indicate specific diseases
Your role as a tech for erythrocyte shapes
Identify if abnormal cells are present
Name the abnormal cells
Quantify the abnormal cells
Schistocytes look like and are a result of
These are RBC fragments
They are generally the result of shearing the cell from intravascular trauma
Echinocytes look like
Have short, evenly spaced, blunt to sharp surface projections that are uniform in size and shape
Often an artefact from drying the slide too slowly, being refrigerated, or put in a hypertonic solution
Can be due to pathological processes
Echinocytes are classified as and how to tell the difference
Echinocyte 1 (crenated cells)- very short projections
Echinocyte 3 (Burr cells)- very thin, tall, quill like projections
Projections are of equal length and are evenly spaced over the periphery of the cell