This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vasculitis, Subject name: Medicine
ACNA is sensitive and specific for : 
Select and explain. 
A. Post streptococcal glomerulonephritis, B. Idiopathic cresentic glomerulonephritis., C. Diffuse glomerulosclerosis, D. Henoch's schonlein purpura
B: Idiopathic cresentic glomerulonephritis.
Answer: B: Idiopathic cresentic glomerulonephritis. 
Explanation: Ans. is 'b' Idiopathic crescentic glomerulonephritis