Page 111 - Clinical Hematology Atlas
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CHAPTER 10 VARIATIONS IN SIZE AND COLOR OF ERYTHROCYTES 95
Anisocytosis is the variation in red blood cell (RBC) diameter (or RBC volume) on a blood
film. This variation correlates with the electronically determined red blood cell distribution
width (RDW). An RDW greater than 14.5% indicates a heterogenous population of RBCs
and a variety of sizes of RBCs should be seen. A low RDW is of no significance.
ANISOCYTOSIS
A B
FIGURE 10–2A Heterogeneous population of FIGURE 10–2B When two distinct populations
erythrocytes, indicating anisocytosis (RDW of RBCs are seen, it is termed a dimorphic
. 14.5%). population (RDW . 14.5%).
Associated with: Anemias, especially iron deficiency, Associated with: Transfusion, myelodysplastic
megaloblastic and hemolytic syndromes, vitamin B 12 , folate, or iron
deficiencies—early in treatment process
