Abnormally small red blood cells with MCV < 80 fL are described as:

• A. Macrocytic
• B. Microcytic
• C. Megaloid
• D. Morphologic

Answer: (B)

Microcytosis describes red blood cells that are smaller than normal, defined by an MCV below 80 fL. The mean corpuscular volume measures the average size of RBCs, so a value under 80 fL pulls the cells toward a smaller size category. This is typically seen in conditions that impair hemoglobin synthesis, such as iron deficiency anemia, certain thalassemias, and sideroblastic anemia. In contrast, macrocytosis would mean larger cells (MCV well above 100 fL), which appears with B12 or folate deficiency, liver disease, or reticulocytosis. Megaloid or megaloid-like terms aren’t standard descriptors for small cells, and morphologic refers to overall appearance rather than size. So, the abnormally small red blood cells described by an MCV < 80 fL are microcytic.