This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
What does Serum ferritin level 
Select and explain. 
A. Decreased capacity to absorb iron, B. Microcytic hypochromic anemia, C. Absent body iron stores, D. Sideroblastic anemia
C: Absent body iron stores
Answer: C: Absent body iron stores 
Explanation: The serum ferritin level is the laboratory test to estimate iron stores. As iron stores are depleted, the serum ferritin falls to Reference: Harrisons Principles of Internal Medicine, 18th Edition, Page 847