Erythrocyte Morphology Normal Morphology Size abnormalities Shape abnormalities
Erythrocyte Morphology Normal Morphology Size abnormalities Shape abnormalities Color abnormalities RBC Inclusions
Normal Erythrocyte Morphology • Most common of blood cells on a blood smear • Biconcave disc • No nuclei in mammal RBC’s • Nuclei present normally in bird and reptile blood • Normal canine RBC’s have a central pallor (lightness) to them
Erythrocytes on a Needle
RBC Size & Pigment • Normocytic • Macrocytic • Microcytic • Normochromic • Hypochromic • No such thing as “Hyperchromic” • Why?
Erythrocyte Size Abnormalities • Record abnormal findings under “General Comments” on the hemogram • Anisocytosis • Macrocytes • Microcytes • Normocytic
Erythrocyte Shape Abnormalities (Poikilocytosis) Schistocytes Acanthocytes Crenation (Echinocytes) Keratocytes Spherocytes Target Cells (Codocytes)
Erythrocyte Shape Abnormalities • Poikilocytosis – general term for shape abnormalities
Schistocytes • RBC fragments
Acanthocytes (Spur cells) • Unevenly distributed surface projections of different lengths
Crenation • Echinocytes (Burr cells) – spiculated (pointed) cells with short, evenly spaced surface projections • Artifact? – slow drying of blood films • Feline blood
Crenation (Echinocytes)
Keratocytes • Helmet cells – contain a vacuole?
Spherocytes • Darkly staining RBC’s with no central pallor Canine only? • Autoimmune hemolytic anemia
Target Cells (Codocytes) • RBCs with central rounded area of hemoglobin surrounded by clear zone • A few in normal blood? • Associated with anemias
Target Cells
Erythrocyte Color Abnormalities • Normochromic • Polychromasia – polychromatophilic RBCs • Blue tint to cytoplasm, due to presence of organelles remaining in cytoplasm (young cells) • Hypochromic – decreased staining due to insufficient hemoglobin in cells Hyperchromic (no such thing!)
RBC Inclusions Reticulocytes Basophilic Stippling Howell-Jolly Bodies Heinz Bodies Nucleated RBCs (NRBCs)
Reticulocytes • Immature RBCs that contain organelles (ribosomes) • As cell matures they are lost • Account for diffuse bluegray stain with Wright’s stain • 1% in normal circulation • Special stains needed usually
Basophilic Stippling • Presence of small, darkblue bodies all over RBC • Represents residual RNA • Common in immature RBCs
Howell-Jolly Bodies • Basophilic nuclear remnants • Seen in young RBCs in response to anemia • Phagocytes in spleen remove these remnants
Heinz Bodies • Rounded structures representing denatured hemoglobin • Pale or blue area, depending on stain • Cause: certain oxidants or drugs • Normal cats may have them
Heinz Bodies
Nucleated RBCs (NRBCs) • Also called metarubricytes • Represent early release of immature cells during anemia • If > than 5 per 100 WBC’s • Correct WBC Count • Normal in bird & reptile blood
NRBC’s – How Many Do You See?
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