The key difference between microcytic and macrocytic anemia is that microcytic anemia is a condition with smaller red blood cells, having an MCV value below 80 femtoliters per cell while macrocytic anemia is a condition with larger red blood cells, having an MCV value above 100 femtoliters per cell.
Anemia is a condition with low levels of circulating red blood cells or low concentration of hemoglobin in red blood cells. It is a result of several factors including inadequate RBC production, excessive RBC destruction, or blood loss. Anemia can be microcytic, normocytic or macrocytic anemia based on the size of RBCs or MCV. MCV (mean corpuscular volume) is the average red blood cell volume, referring to the actual size of the cells themselves. In microcytic anemia, red blood cells are smaller than the normal size while in macrocytic anemia, red blood cells are larger than the normal size.
CONTENTS
1. Overview and Key Difference
2. What is Microcytic Anemia
3. What is Macrocytic Anemia
4. Similarities Between Microcytic and Macrocytic Anemia
5. Side by Side Comparison – Microcytic vs Macrocytic Anemia in Tabular Form
6. Summary
What is Microcytic Anemia?
MIcrocytic anemia is one of the three types of anemia conditions. It is the condition of having smaller red blood cells than normal. Therefore, microcytic anemia is characterized by a small MCV of below 80 fL. Furthermore, microcytic anemia most commonly occurs due to iron deficiency caused by the absence of iron stored in bone marrows. Also, this condition can be caused due to lead poisoning, anemia of chronic disease, sideroblastic anemia, and thalassemia.
Figure 01: Microcytic Anemia
What is Macrocytic Anemia?
Macrocytic anemia is a condition in which the red blood cells are larger than the average size. In macrocytic anemia, MCV of red blood cells is above 100 fL. Due to the larger sizes of red blood cells, there are low numbers of red blood cells in the blood. Thus, this causes low levels or insufficient levels of hemoglobin per cell.
Red blood cells become larger when they fail to produce DNA quickly enough to divide at the right time as they grow. Therefore, macrocytic anemia most commonly occurs as a result of megaloblastic anaemia. Moreover, macrocytic anemia can be caused due to liver disease, hemoglobinopathies, metabolic disorders, marrow disorders and increased destruction.
What are the Similarities Between Microcytic and Macrocytic Anemia?
- Microcytic and macrocytic anemia are two of the three types of anemia based on the size of the red blood cells.
- In both conditions, the average volume of the red blood cell differs than the normal size of a red blood cell.
- Bone marrow failure can manifest with both types of anemia.
What is the Difference Between Microcytic and Macrocytic Anemia?
Microcytic anemia is the condition of having smaller red blood cells than normal while macrocytic anemia is the condition in which the red blood cells are larger than the normal size. So, this is the key difference between microcytic and macrocytic anemia. In microcytic anemia, red blood cells have a smaller MCV (below 80 fL) while in macrocytic anemia, red blood cells have a larger MCV (above 100 fL).
Moreover, another difference between microcytic and macrocytic anemia is that microcytic anemia mainly occurs due to the deficiency of haemoglobin production, such as iron deficiency or thalassaemia, while macrocytic anemia mainly occurs due to the problems with the synthesis of the blood cells, as in vitamin B12 or folic acid deficiency.
Summary – Microcytic vs Macrocytic Anemia
Microcytic anemia is characterized by smaller red blood cells, having a small MCV value below 80 fL. In contrast, macrocytic anemia is characterized by too larger red blood cells, having a large MCV value above 100 fL. So, this is the key difference between microcytic and macrocytic anemia. In both conditions, the blood has low levels of hemoglobin. Iron deficiency is the most common cause of microcytic anemia while megaloblastic anaemia is the most common cause of macrocytic anemia. Bone marrow failure can manifest with both types of anemia.
Reference:
1. Massey, A C. “Microcytic Anemia. Differential Diagnosis and Management of Iron Deficiency Anemia.” The Medical Clinics of North America, U.S. National Library of Medicine, May 1992, Available here.
2. “Anemia.” – Knowledge for Medical Students and Physicians, 5 Mar. 2020, Available here.
Image Courtesy:
1. “Microcytosis” By Prof. Osaro Erhabor – Prof. Osaro Erhabor (CC0) via Commons Wikimedia