This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Neonatal sepsis, Subject name: Pediatrics
Definitive test for the diagnosis of neonatal sepsis is? 
Select and explain. 
A. Blood culture, B. Urine culture, C. Immature:Total neutrophil ratio, D. Sepsis screen
A: Blood culture
Answer: A: Blood culture 
Explanation: Blood culture: gold standard for diagnosis of sepsis - performed in all cases of suspected sepsis prior to staing antibiotics