ASCP Specialist in Hematology (SH) 2025 – 400 Free Practice Questions to Pass the Exam

Megaloblastic anemia is characterized by the presence of large, immature red blood cells (RBCs) in the bone marrow and peripheral blood. When examining laboratory findings, an increased mean corpuscular volume (MCV) is a hallmark indicator of this condition. This increase in MCV occurs because the erythrocytes are larger than normal due to impaired DNA synthesis, which is often a result of vitamin B12 or folate deficiency.

In megaloblastic anemia, the maturation process of red blood cells in the bone marrow is disrupted, leading to the production of macrocytic (larger) red blood cells. This is why an elevated MCV is a key laboratory finding for diagnosing megaloblastic anemia.

In contrast, low mean corpuscular volume or normal red blood cell size would not be consistent with megaloblastic anemia, which is defined by the presence of larger-than-normal red blood cells. Additionally, the presence of microcytic red blood cells is typically associated with other types of anemia, such as iron deficiency anemia, rather than megaloblastic anemia. Thus, the finding of increased MCV directly supports the diagnosis of megaloblastic anemia.