Increased mean corpuscular volume Increased MCV Macrocytosis refers to a mean cell volume (MCV) greater than 100 fL. If macrocytosis is an isolated abnormality, the amount of hemoglobin in the cell increases proportionately, so the mean cell hemoglobin concentration (MCHC) remains within normal limits. HP:0005518 UMLS:C0855791 Larger than normal size of erythrocytes. Erythrocyte macrocytosis HP:0005536 Abnormal mean corpuscular volume