1. Red Blood Cells
Erythrocytes (RBC’s)

2. Formed Elements (Cells) of Blood
Red blood cells (erythrocytes)
Platelets (special cell fragments)

3. Hemograms A written record of the CBC Includes the following:
RBC indices
WBC indices
Platelet evaluation
General Comments on any unusual findings

4. Erythrocytes

5. Erythrocyte Terminology
Erythrocyte function
Erythron
Erythrocyte (RBC)

6. RBC Count Use of hemocytometer Use of electronic cell counters
Technique the same as for WBC Count, except dilution factors and counting areas
As much as a 20% error!!!
Use of electronic cell counters
More accurate than hemocytometers
Formula for rough estimate of RBC Count
RBC Count = PCV/6
results in millions per microliter

8. 3 Erythrocyte Indices Mean Corpuscular Volume (MCV)
SIZE of the average RBC
Helpful in determining what type of anemia might be present
Mean Corpuscular Hemoglobin (MCH)
Average WEIGHT of hemoglobin in the average RBC
Not very helpful
Mean Corpuscular Hemoglobin Concentration (MCHC)
Average CONCENTRATION of hemoglobin in the average RBC

11. Erythrocyte Morphology
Normal Morphology
Size abnormalities
Shape abnormalities
Color abnormalities
RBC Inclusions

12. 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

14. Erythrocytes on a Needle

15. RBC Size & Pigment Normocytic Macrocytic Microcytic Normochromic
Hypochromic
No such thing as “Hyperchromic”
Why?

17. Erythrocyte Size Abnormalities
Record abnormal findings under “General Comments” on the hemogram
Anisocytosis
Macrocytes
Microcytes
Normocytic

20. Erythrocyte Shape Abnormalities (Poikilocytosis)
Schistocytes
Acanthocytes
Crenation (Echinocytes)
Keratocytes
Spherocytes
Target Cells (Codocytes)

21. Erythrocyte Shape Abnormalities
Poikilocytosis – general term for shape abnormalities

24. Schistocytes
RBC fragments

25. Acanthocytes (Spur cells)
Unevenly distributed surface projections of different lengths

27. Crenation
Echinocytes (Burr cells) – spiculated (pointed) cells with short, evenly spaced surface projections
Artifact? – slow drying of blood films
Feline blood

28. Crenation (Echinocytes)

29. Keratocytes
Helmet cells – contain a vacuole?

30. Spherocytes Darkly staining RBC’s with no central pallor Canine only?
Autoimmune hemolytic anemia

31. Target Cells (Codocytes)
RBCs with central rounded area of hemoglobin surrounded by clear zone
A few in normal blood?
Associated with anemias

32. Target Cells

33. 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!)

35. Nucleated RBCs (NRBCs)
RBC Inclusions
Reticulocytes
Basophilic Stippling
Howell-Jolly Bodies
Heinz Bodies
Nucleated RBCs (NRBCs)

36. Reticulocytes Immature RBCs that contain organelles (ribosomes)
As cell matures they are lost
Account for diffuse blue-gray stain with Wright’s stain
1% in normal circulation
Special stains needed usually

38. Basophilic Stippling Presence of small, dark-blue bodies all over RBC
Represents residual RNA
Common in immature RBCs

40. Howell-Jolly Bodies Basophilic nuclear remnants
Seen in young RBCs in response to anemia
Phagocytes in spleen remove these remnants

42. Heinz Bodies Rounded structures representing denatured hemoglobin
Pale or blue area, depending on stain
Cause: certain oxidants or drugs
Normal cats may have them

43. Heinz Bodies

47. 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

49. NRBC’s – How Many Do You See?