Macrocytosis

Excerpt

Macrocytosis refers to the finding of enlarged red blood cells (RBCs). The measurement of RBC size is reported in the complete blood count (CBC) as mean corpuscular volume (MCV). Most elevated MCV reports are accompanied by an elevated mean corpuscular hemoglobin (MCH). The elevation of MCV and/or MCH suggests macrocytosis. In some cases, the discovery of macrocytosis may not necessitate further testing or treatment. However, practitioners should understand the importance of macrocytosis in the potential development of clinically significant anemia (macrocytic anemia), and they should understand the range of pathology that macrocytosis may signify, often implicating extra-hematologic organ systems. Close attention to historical, physical exam, and laboratory findings is helpful in determining the underlying etiology, which, in turn, dictates management strategies for patients with macrocytosis.