This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Nutritional anemia, Subject name: Pediatrics
First change of improvement noted after iron therapy is initiated: 
Select and explain. 
A. Decreased irritability, B. Reticulocytosis, C. Increase in serum iron levels, D. Replenishment of iron stores
A: Decreased irritability
Answer: A: Decreased irritability 
Explanation: RESPONSE TO TREATMENT IN IRON DEFICIENCY ANEMIA: Time after Iron administration Response 12-24 hours Decreased irritability, increased appetite 48-72 hours Reticulocytosis, peaks at 5-7 days post treatment 4-30 days Increase in Hb level (best measure) 1-3 months Repletion of stores