Final answer:
Megaloblastic anemia is a true cause of macrocytic anemia, featuring larger-than-normal RBCs due to vitamin B12 and/or folate deficiencies. By examining RBC size through the mean corpuscle volume (MCV), clinicians can diagnose macrocytic anemia, as an increased MCV is a typical finding in megaloblastic anemia.
Step-by-step explanation:
It is true that megaloblastic anemia is a cause of macrocytic (MCV) anemia. Megaloblastic anemia is characterized by the presence of large, structurally abnormal red blood cells (RBCs), which are larger-than-normal, and is therefore classified as a macrocytic anemia. This condition stems from deficiencies in essential nutrients, specifically vitamin B12 and/or folate, which are vital for DNA synthesis and the maturation of RBCs.
Lack of dietary intake, issues with nutrient absorption, or other health factors can lead to megaloblastic anemia. Factors such as a diet deficient in meat or alternative sources of B12, overcooking or consuming insufficient quantities of vegetables may lead to a lack of folate. In contrast, conditions like pernicious anemia can impair the absorption of vitamin B12.
Anemias can be categorized by their kinetic and morphological features. Using the morphological approach, which focuses on the RBCs themselves and their size, a common diagnostic test employed is the mean corpuscle volume (MCV). Megaloblastic anemia, due to its macrocytic nature, often shows an increased MCV. This means the RBCs are larger than the normal size (normocytic) and are not smaller-than-normal (microcytic).