From the Research
Classic iron deficiency anemia is characterized by laboratory findings including microcytic hypochromic red blood cells with decreased mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH), low serum iron levels, elevated total iron binding capacity (TIBC), decreased transferrin saturation, and depleted ferritin stores. The diagnosis of iron deficiency anemia can be challenging, but certain laboratory parameters are helpful in making an accurate diagnosis.
- Key laboratory findings include:
- Decreased MCV and MCH, indicating microcytic hypochromic anemia
- Low serum iron levels, which can be measured directly
- Elevated TIBC, which reflects the body's attempt to increase iron transport
- Decreased transferrin saturation, typically below 15%
- Depleted ferritin stores, usually less than 30 ng/mL, which is a sensitive indicator of iron deficiency A peripheral blood smear may show microcytic red cells with increased central pallor and poikilocytosis, and red cell distribution width (RDW) is typically elevated, indicating variation in red cell size 1. As the condition progresses, hemoglobin and hematocrit levels decrease, reflecting the reduced oxygen-carrying capacity of the blood. Bone marrow examination, though rarely necessary, would show absent iron stores when stained with Prussian blue. These laboratory abnormalities reflect the body's inability to incorporate iron into hemoglobin molecules due to depleted iron stores, resulting in the production of smaller red blood cells with reduced hemoglobin content. The increased TIBC represents the body's attempt to maximize iron transport capacity in response to iron deficiency 2, 3, 4, 5.