This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Pathology of Conception, Subject name: Gynaecology & Obstetrics
All are done in quadruple test in downs syndrome except: 
Select and explain. 
A. AFP, B. HCG, C. PAPP, D. inhibin-A
C: PAPP
Answer: C: PAPP 
Explanation: Ref: Dutta Textbook of Obstetrics 5th ed pg 493Explanation:Triple TestMS AFPL'nconjugated estrio! HCG 'Quadruple TestMS AFPUE3HCGInhibin-AIntegrated TestNTPAPP-AHCGDowns SyndromeIncreased Inhibin -AIncreased HCGDecreased MSAFPDecreased PAPPDecreased UE3