This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S., Subject name: Pediatrics
Serious infections can occur when absolute neutrophil count decreases to? 
Select and explain. 
A. Less than 500/mL, B. Less than 800/mL, C. Less than 1000/mL, D. Less than 1500/mL
A: Less than 500/mL
Answer: A: Less than 500/mL 
Explanation: a. Less than 500/mL(Ref: Nelson's 20/e p 1048, Ghai 8/e p 357)Serious infections are most likely when the neutrophil count falls below 500 per mm3.