Low MCV (Mean Corpuscular Volume) means that the red blood cells (RBCs) are smaller than normal, a condition known as microcytosis or microcytic anemia. This typically indicates that the average size of red blood cells is below 80 femtoliters (fL)

. Common causes of low MCV include:

• Iron deficiency anemia, the most frequent cause, where there is insufficient iron to produce normal-sized RBCs

• Thalassemia, a genetic disorder leading to abnormal hemoglobin production and smaller RBCs

• Lead poisoning, which interferes with hemoglobin synthesis

• Chronic diseases causing impaired RBC production

• Sideroblastic anemia and other less common causes such as vitamin deficiencies, heavy alcohol consumption, and certain medications

Symptoms associated with low MCV/microcytic anemia may include:

• Fatigue and weakness
• Shortness of breath
• Dizziness
• Pale skin
• Hair loss and nail changes in some cases

Diagnosis and treatment:
Low MCV alone is not enough for a definitive diagnosis; it is interpreted alongside other blood tests and clinical symptoms

. Treatment depends on the underlying cause, for example:

• Iron supplements and vitamin C for iron deficiency anemia, often over several months

• Specific therapies for chronic diseases, lead poisoning, or genetic conditions like thalassemia

In summary, low MCV indicates smaller-than-normal red blood cells, most commonly due to iron deficiency anemia or genetic conditions affecting hemoglobin, and requires further evaluation to determine the exact cause and appropriate treatment