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: Unknown
Patient presenting with cutaneous vasculitis, glomerulonephritis, peripheral neuropathy, which of the following will help in diagnosis? 
Select and explain. 
A. ANCA, B. RA factor, C. Hbsag, D. MIF
A: ANCA
Answer: A: ANCA 
Explanation: Ref. API Textbook of Medicine. Pg. 1313
 
Cutaneous vasculitis features – Diagnosis
Anti-neutrophil cytoplasmic antibodies (ANCAs):

Group of autoantibodies
IgG type mainly,
Produced against antigens in cytoplasm of neutrophil granulocytes & monocytes.
Particularly associated with systemic vasculitis, so called “ANCA-associated vasculitis”.
c-ANCA – Abs against MPO, p-ANCA -  Abs Against PR3