What is the most common cause of microcytic anemia?

Microcytic anemia is characterized by the presence of smaller than normal red blood cells, which can occur due to several underlying conditions. The most common cause of microcytic anemia is iron deficiency. This condition arises when there is insufficient iron available for the production of hemoglobin, the protein in red blood cells that carries oxygen.

When iron levels are low, the body is unable to produce adequate amounts of hemoglobin, leading to the formation of smaller red blood cells. This is particularly noticeable in laboratory tests, where the mean corpuscular volume (MCV) of red blood cells is found to be reduced, indicating they are microcytic.

While vitamin B12 deficiency, folic acid deficiency, and chronic disease can lead to other types of anemia, they do not typically present as microcytic anemia. Vitamin B12 and folic acid deficiencies are more often associated with macrocytic anemia, where larger than normal red blood cells are produced due to inadequate DNA synthesis. Chronic disease can cause normocytic anemia where red blood cell size remains normal but the number is reduced due to inflammation or other underlying health issues.

Therefore, recognizing iron deficiency as the predominant cause of microcytic anemia is fundamental for effective diagnosis and treatment in laboratory medicine.