1. Erythrocytic Morphology and Associated Diseases(Size and Shape)
Bindu Panapalli

2. Normocytes
Normal erythrocytes

3. Macrocytes Erythrocytes that have an MCV >100 fL.
Seen in megaloblastic anemias, such B12/folate as deficiency.
Occurs in anemia of liver disease.

4. Microcytes a. Are small RBC’s less than 6 micrometers in diameter.
b. Shows an MCV >80 fL
c. Seen in iron deficiency anemias, thalassemias, hemolytic anemias, sideroblastic anemias, and chronic disorder anemias.

5. Echinocyctes Crenated RBC
Show uniform round bumps or spikes on the RBC surface.
Usually indicates artifacts of staining or increased platelets.
No pathology is indicated.
Caused by changes in cellular osmotic pressure.

6. Burr cell Keratocyctes. Irregular in size with spiny projections.
Seen in renal insufficiency, liver disease, ulcers, and heparin therapy.
Caused by cell membrane breakup due to cytoplasmic vacuoles.
Can be confused with crenated erythrocyctes.

7. Acanthocytes
Appear as small, densely stained RBCs with multiple irregularly spaced spikes or clublike projections.
Associated MAHA(microangiopathic hemolytic anemia), alcoholic liver diseases, hereditary acanthocytosis, and abetalipoproteinemia.
Caused by excessive cholesterol in the membrane.

8. Target Cells Codocytes or Mexican hat.
Show a central area of hemoglobin surrounded by colorless ring and a peripheral ring of hemoglobin.
Considered artifacts if appears in only one section of the smear.
Seen in liver disease, Hb SS,SC, S thalassemia, thalassemia, iron deficiency, and postplenectomy

9. Spherocytes Slightly smaller (6.2-7.0 microliter) than normal RBC.
Show no central pallor.
Normal MCV, increased MCHC, and increased osmotic fragility.
Seen in burns, hereditary spherocytosis, and extravascular hemolytic processes.
Microspherocyctes are frequently seen in severe burn cases.
Spherocyctes and microspherocytes result when the RBC surface area decrease due to a decrease in cell volume.

10. Teardrops Dacryocytes Tennis racquet cell
Show a tapered and round end. Slightly smaller than normocytes.
Usually microcytic and/or hypochromic
Abnormality is associated with myeloproliferative syndrome, pernicious anemias, ineffective erythropoiesis, thalassemia, and myelophthisic anemia.

11. Sickle Cells
Shapes vary but show thin, elongated pointed ends, and appear crescent shaped.
Contains hemoglobin S.
Seen in sickle cell anemia.
Cell shape is caused by cell membrane alterations due to hemoglobin S.
Decreased osmotic fragility.

12. Helmet Cells Keratocytes
Interior portion of the cell is hollow, resembling a helmet.
These cell fragment are formed in the spleen and intravascular fibrin clots.
Asscociated with microangiopathic hemolytic anemia.

13. Schistocytes RBC fragment.
RBC fragmentation results from passage through damaged or altered blood vessels.
Variety of shapes : triangular, comma-shaped, helmet shaped.
Microcytic
May be found whenever blood vessel pathology is present.
Seen in DIC, burns, renal transplant rejection and hemolytic processes.

14. Stomatocytes
Characterized by an elongated or slitlike area of central pallor that resembles a mouth.
Stomatocytes results from increased sodium and decreased potassium concentration within the cytoplasm of RBC.
Seen in hereditary stomatocytosis, obstructive liver disease, alcoholism.

15. Elliptocytes Ovalocytes Cells have rod, cigar, or sausage shape.
Caused by membrane integrity defect.
Seen in hereditary elliptocytosis, iron deficiency anemias, megaloblastic anemia, thalassemia, and sickle cell anemia.

16. Nucleated RBC
nRBCs
Most are orthochromic normoblast but can appear in any erythrocytic stage of maturation.
Indicate some type of bone marrow stimulation or increased erythropoiesis.
Normally found in newborns.
Seen in acute blood loss, leukemias, hypoxia,megaloblastic anemias, heart disease, and myelofibrosis.
As few as one nRBC should be reported when seen on adult peripheral slide.