A 35-year-old woman visits her primary care physician due to a 4-month history of fatigue, exercise intolerance, and palpitations. She notes that her menstrual cycles, which previously lasted 4 days, now last 7 to 8 days with heavy flow. She denies any recent travel or systemic symptoms such as fever or weight loss. Past medical history is otherwise unremarkable. She does not take any medications and follows a balanced diet. Physical examination reveals conjunctival pallor and tachycardia at 105/min. Laboratory evaluation shows a hemoglobin of 9.2 g/dL, mean corpuscular volume of 72 fL, and a platelet count of 480,000/μL. A peripheral blood smear demonstrates hypochromic, microcytic red blood cells.
Which of the following iron study profiles is most consistent with the patient's presentation?
The correct answer is:
A) Decreased ferritin, decreased serum iron, increased total iron-binding capacity
This patient presents with signs and symptoms of iron deficiency anemia caused by chronic blood loss from menorrhagia. In iron deficiency anemia, the body's iron stores are depleted, leading to a decrease in serum ferritin, which is the most sensitive marker for iron stores. Serum iron levels decrease because there is insufficient iron available for erythropoiesis. To compensate for the low iron levels, the liver increases the production of transferrin, the protein responsible for transporting iron in the blood. This results in an increase in the total iron-binding capacity, which measures the potential of transferrin to bind iron.
Answer choice B: Decreased ferritin, increased serum iron, decreased total iron-binding capacity, is incorrect. This pattern does not correspond to a classic clinical anemia profile. Iron deficiency typically involves both low serum iron and elevated total iron-binding capacity.
Answer choice C: Increased ferritin, decreased serum iron, decreased total iron-binding capacity, is incorrect. This profile is characteristic of anemia of chronic disease, also known as anemia of inflammation. In this condition, inflammatory cytokines such as hepcidin lead to iron sequestration within macrophages and decreased iron absorption, resulting in high ferritin levels and decreased total iron-binding capacity.
Answer choice D: Increased ferritin, increased serum iron, increased total iron-binding capacity, is incorrect. This pattern is consistent with iron overload conditions, such as hereditary hemochromatosis. Patients with iron overload have high iron stores and elevated serum iron, often resulting in high ferritin and low total iron-binding capacity due to transferrin saturation.
Answer choice E: Normal ferritin, decreased serum iron, increased total iron-binding capacity, is incorrect. While this shows low iron and high total iron-binding capacity, normal ferritin is not consistent with established iron deficiency anemia. Ferritin is the first value to decrease when iron stores are depleted.
Key Learning Point
Iron deficiency anemia presents with microcytic, hypochromic red blood cells and a specific iron study profile: low serum ferritin, low serum iron, and elevated total iron-binding capacity. This contrasts with anemia of chronic disease, which typically features normal or elevated ferritin and decreased total iron-binding capacity.
