What are the causes of low Mean Corpuscular Volume (MCV)?

From the Guidelines

Low MCV is primarily caused by iron deficiency anemia, thalassemia, and anemia of chronic disease, as evidenced by the most recent study 1. The causes of low MCV can be broken down into several categories, including:

• Iron deficiency anemia, which occurs when the body lacks sufficient iron to produce hemoglobin, often due to blood loss, poor dietary intake, or malabsorption issues like celiac disease 1.
• Thalassemia, a genetic disorder affecting hemoglobin production, results in smaller red blood cells regardless of iron status 1.
• Anemia of chronic disease, which can be caused by chronic conditions like kidney disease, inflammatory disorders, and certain cancers that impair iron utilization, leading to low MCV 1. Other causes of low MCV include:
• Lead poisoning, which interferes with heme synthesis 1.
• Sideroblastic anemia, where iron cannot be properly incorporated into hemoglobin 1.
• Certain medications like antiretrovirals and chemotherapy agents that can suppress bone marrow function and reduce MCV 1. Diagnosis of low MCV typically involves a complete blood count, peripheral blood smear, iron studies, and possibly hemoglobin electrophoresis or genetic testing for thalassemia 1. Treatment depends on addressing the underlying cause, such as iron supplementation for deficiency, specific management for thalassemia, or treating chronic conditions 1. It is essential to investigate anaemia with red cell distribution width (RDW), mean corpuscular volume (MCV), reticulocyte count, full blood count (FBC), ferritin, transferrin saturation, and CRP levels to determine the cause of low MCV 1.

From the Research

Causes of Low MCV

The causes of low Mean Corpuscular Volume (MCV) can be attributed to several factors, including:

• Iron deficiency anemia, which is the most common cause of microcytic anemia 2, 3, 4
• Anemia of chronic disease, which can result from infectious, inflammatory, or malignant processes 5, 6, 4
• Thalassemia, a genetic disorder that affects the production of hemoglobin 2, 3
• Sideroblastic anemia, a rare disorder characterized by the accumulation of iron in the mitochondria of red blood cells 2, 3
• Other congenital and acquired causes, such as sickle cell anemia and iron chelation 3

Acquired Causes

Acquired causes of low MCV include:

• Iron deficiency due to blood loss, menstruation, pregnancy, or gastrointestinal bleeding 2, 4
• Anemia of chronic disease, which can be caused by chronic inflammatory, infectious, or neoplastic disorders 6, 4
• Malabsorption of iron, which can lead to iron deficiency anemia 2

Congenital Causes

Congenital causes of low MCV include:

• Thalassemia, a genetic disorder that affects the production of hemoglobin 2, 3
• Sickle cell anemia, a genetic disorder that affects the shape of red blood cells 3
• Other inherited disorders that affect the production of hemoglobin or the structure of red blood cells 3