Iron deficiency anaemia is classified as which morphologic type?

• A. Macrocytic
• B. Microcytic
• C. Normocytic
• D. Hypochromic

Answer: (B)

The main idea here is that anemia is often first classified by the size of the red blood cells. In iron deficiency, there isn’t enough iron to make hemoglobin, so red blood cells don’t mature fully and end up smaller than normal. That makes the anemia microcytic, meaning the mean corpuscular volume is decreased. These microcytic cells are typically less colored as well (hypochromic), but the key morphologic hallmark is the small size.

In contrast, macrocytic anemia features large red cells (often from B12 or folate deficiency), and normocytic anemia has normally sized cells (seen in early iron deficiency or anemia of chronic disease). Hypochromia describes pale cells due to low hemoglobin content and can accompany microcytosis, but it’s about color, not size.