Which CBC parameter indicates the degree of anisocytosis?

The correct answer, RDW (Red Cell Distribution Width), is significant because it specifically measures the variability in red blood cell size, which is indicative of anisocytosis. Anisocytosis refers to a condition where red blood cells are of unequal sizes, and RDW gives a quantitative measure of this variation. A higher RDW value suggests greater anisocytosis, reflecting a wider distribution of red blood cell volumes.

MCV (Mean Corpuscular Volume) measures the average volume of red blood cells but does not assess the variability or distribution of sizes among them, which limits its use in evaluating anisocytosis specifically. HCT (Hematocrit) provides the proportion of blood volume that is occupied by red blood cells, and while it informs about overall red blood cell content, it does not indicate variability in red blood cell sizes. Hemoglobin concentration indicates the oxygen-carrying capacity of the blood and is not related to the size variation of the red blood cells. Therefore, RDW is the most relevant parameter for assessing anisocytosis in a complete blood count (CBC).