What is a key laboratory finding indicative of iron deficiency anemia in a patient?

A key laboratory finding indicative of iron deficiency anemia is a low ferritin level, such as 15 ng/mL. Ferritin is a protein that stores iron in the body, and low levels indicate depleted iron stores, which is a hallmark of iron deficiency anemia. This condition typically presents with low ferritin levels, which provide a reliable measure of the body's iron reserves.

While a hemoglobin level of 8 g/dL can demonstrate anemia, it is not specific for iron deficiency as there are various causes of anemia that may present with similar hemoglobin levels. A total iron-binding capacity (TIBC) of 470 µg/dL indicates the body's ability to bind iron is increased, which is commonly associated with iron deficiency; however, TIBC is not as definitive as ferritin levels in confirming iron deficiency anemia specifically.

A mean corpuscular volume (MCV) of 70 fL suggests microcytic anemia, which often aligns with iron deficiency, but it does not provide a definitive measure of iron status on its own. Therefore, the presence of a low ferritin level is the most direct indicator of iron deficiency anemia, as it reflects the reduced iron stores necessary for red blood cell production.