Table 5 Predictive values of maternal free β- hCG, AFP MoM, and risk value of Trisomy 21 for Trisomy 21

Non-AMA

197,101

 free β- hCG (MoM)

0.784

0.703–0.865

< 0.001

2.055

0.675

0.881

0.506

 AFP (MoM)

0.699

0.618–0.779

< 0.001

0.795

0.675

0.760

0.385

 Risk value of Trisomy 21

0.856

0.792–0.920

< 0.001

1/780

0.792

0.862

0.654

AMA

12,739

 free β- hCG (MoM)

0.783

0.680–0.885

< 0.001

1.725

0.679

0.805

0.483

 AFP (MoM)

0.767

0.668–0.865

< 0.001

0.925

0.821

0.656

0.477

 Risk value of Trisomy 21

0.858

0.780–0.936

< 0.001

1/172

0.714

0.866

0.580