Anisocytosis

Anisocytosis refers to the presence of red blood cells of varying sizes. Anisocytosis is reported as “slight” to 4+ (“four plus”) and gives the same information as the RDW parameter (red blood cell distribution width): the larger the size variation in the red blood cells, the higher the anisocytosis and RDW results will be. Like the RDW, anisocytosis must be interpreted in association with other red cell indices, including the MCV (mean corpuscular or cell volume). Anisocytosis (or a high RDW) is generally associated with iron deficiency anemia, B12 or folic acid insufficiency, or abnormal bone marrow (myelodysplastic syndromes).