What is a characteristic finding in patients with iron deficiency anemia?

In the context of iron deficiency anemia, low ferritin is a characteristic finding because ferritin is a protein that stores iron in the body. When a patient has iron deficiency anemia, the body's iron stores are depleted, leading to a decrease in ferritin levels. This low level of ferritin is a direct indicator of iron deficiency and is commonly evaluated in clinical settings to confirm the diagnosis.

In contrast, high mean corpuscular volume (MCV) typically indicates macrocytic anemia, which is associated with deficiencies in vitamin B12 or folate, not iron deficiency. An elevated reticulocyte count may occur in the response to anemia but is not specific to iron deficiency anemia; reticulocytes can be elevated in various types of anemia when the bone marrow is compensating. Normocytic red blood cells would suggest a different type of anemia, as iron deficiency usually results in microcytic, hypochromic red blood cells due to insufficient iron for hemoglobin production. Thus, low ferritin is a key lab finding that points towards iron deficiency anemia.