In interpreting an MCV that is smaller than normal, which description applies to the cells?

In interpreting an MCV that is smaller than normal, which description applies to the cells?

• A. Cells larger than normal
• B. Cells smaller than normal
• C. Normal-sized cells
• D. Variably sized cells

Answer: (B)

A decreased MCV indicates red blood cells are smaller than normal, a condition called microcytosis. The MCV measures the average size of red blood cells, so a lower value points to smaller cells. If MCV were high, that would mean macrocytosis (larger cells); if MCV were within the normal range, the cells would be normocytic; and if cells varied in size, that describes anisocytosis rather than a simple microcytic pattern. Therefore, the description that fits a smaller-than-normal MCV is that the cells are smaller than normal.

A decreased MCV indicates red blood cells are smaller than normal, a condition called microcytosis. The MCV measures the average size of red blood cells, so a lower value points to smaller cells. If MCV were high, that would mean macrocytosis (larger cells); if MCV were within the normal range, the cells would be normocytic; and if cells varied in size, that describes anisocytosis rather than a simple microcytic pattern. Therefore, the description that fits a smaller-than-normal MCV is that the cells are smaller than normal.