Anisopoikilocytosis: RBC Size and Shape Variations

Anisopoikilocytosis is a hematologic term used to describe a peripheral blood smear showing significant

variations in both the size and shape of red blood cells (RBCs). It is a combination

of two distinct clinical findings: **anisocytosis** (variation in size) and **poikilocytosis**

(variation in shape). ### **I. Core Components** * **Anisocytosis:** This refers to an

abnormal increase in the range of RBC sizes. It is quantitatively measured by the

**Red Cell Distribution Width (RDW)** on a standard complete blood count (CBC). * **Poikilocytosis:**

This refers to the presence of RBCs with various abnormal shapes, such as target cells,

sickle cells, or schistocytes. ### **II. High-Yield Clinical Associations**