Describe the morphologic appearance of the red cells given the following results

RBC: 1.89 ´ 1012/L
Hemoglobin: 7.5 g/dL
Hematocrit: 21.0%
RDW: 18.5

a. Macrocytic with anisocytosis
b. Normocytic normochromic with anisocytosis
c. Microcytic hypochromic with little anisocytosis
d. Macrocytic with most cells the same size

ANS: A
The red cell indices are calculated as follows: MCV = (7.5/1.89) ´ 10 = 111 fL; mean cell hemoglobin (MCH) = (7.5/1.89) ´ 10 = 40 pg; mean cell hemoglobin concentration (MCHC) = (7.5/21) ´ 100 = 36. The red cells are thus macrocytic (high MCV) and normochromic (normal MCHC). The RDW is elevated at 18.5, so an increased variation in size exists. This then is a macrocytic anemia with anisocytosis.