Variation in red blood cell (RBC) size observed on the peripheral blood smear is described as:
The correct answer and explanation is:
The variation in red blood cell (RBC) size observed on a peripheral blood smear is described as anisocytosis. This term refers to a condition where the RBCs vary in size, with some being smaller (microcytes) and others larger (macrocytes) than normal. The degree of anisocytosis is assessed by examining the blood smear under a microscope, and it can indicate several underlying conditions.
Anisocytosis is commonly seen in disorders such as iron deficiency anemia, megaloblastic anemia, and thalassemia. In iron deficiency anemia, microcytes (smaller RBCs) may be present due to insufficient iron for hemoglobin production. In megaloblastic anemia, macrocytes (larger RBCs) can be observed due to impaired DNA synthesis, which affects the maturation of RBCs. Thalassemia, a genetic disorder affecting hemoglobin production, can also lead to anisocytosis with a mixture of smaller and irregularly shaped RBCs.
The severity of anisocytosis is often graded based on the number of RBCs with abnormal sizes. A slight variation may not be significant, but marked anisocytosis, where there is a prominent difference in RBC size, may suggest a more serious underlying condition. In a clinical setting, the presence of anisocytosis may prompt further investigations, including a complete blood count (CBC), reticulocyte count, and additional tests to determine the cause.
Peripheral blood smears provide valuable diagnostic information for healthcare providers by offering a direct visual assessment of the blood’s cellular components. The identification of anisocytosis, along with other abnormalities like poikilocytosis (variation in RBC shape), can help guide the diagnosis and treatment of various hematological disorders.