Activin A and Follistatin as Biomarkers for Ectopic Pregnancy and Missed Abortion
Table 3
Sensitivity and specificity of activin A, follistatin (FS), and their activin A/FS ratio as serum markers of missed abortions (MA) and ectopic pregnancies (EP) versus those of intrauterine pregnancies (IUP).
Sens. (95% CI)
Spec. (95% CI)
Cut-off point
AUC
value
PPV
NPV
IUP versus MA + EP
Activin A
0.879 (0.718–0.966)
0.850 (0.734–0.929)
504.66
0.912
<0.001
0.527
0.974
Follistat.
0.697 (0.513–0.844)
0.850 (0.734–0.929)
4254.00
0.808
<0.001
0.470
0.936
Activin A/FS
0.727 (0.545–0.867)
0.617 (0.482–0.739)
0.136
0.642
0.024
0.266
0.922
IUP versus MA
Activin A
0.939 (0.798–0.993)
0.700 (0.506–0.853)
402.87
0.845
<0.001
0.356
0.985
Follistat.
0.636 (0.451–0.796)
0.867 (0.693–0.962)
4412.7
0.785
<0.001
0.458
0.931
Activin A/FS
0.818 (0.645–0.930)
0.467 (0.283–0.657)
0.107
0.588
0.231
0.213
0.936
IUP versus EP
Activin A
0.879 (0.718–0.966)
1.000 (0.884–1.000)
504.66
0.979
<0.001
1.000
0.999
Follistat.
0.727 (0.545–0.867)
0.900 (0.735–0.979)
3747.2
0.830
<0.001
0.068
0.997
Activin A/FS
0.727 (0.545–0.867)
0.733 (0.541–0.877)
0.136
0.696
0.008
0.027
0.996
MA versus EP
Activin A
0.633 (0.439–0.801)
0.833 (0.653–0.944)
325.21
0.734
0.002
0.037
0.996
Follistat.
0.600 (0.406–0.773)
0.700 (0.506–0.853)
2848.5
0.621
0.107
0.020
0.994
Activin A/FS
0.500 (0.313–0.687)
0.733 (0.541–0.877)
0.142
0.570
0.352
0.019
0.993
The optimal cut-off points were calculated by Receiver Operating Characteristics (ROC) curve analyses for IUP, MA, and EP. Details of sensitivity, specificity, area under the curve (AUC), negative predictive value (NPV), and positive predictive value (PPV) of serum markers. Values are PPV and NPV for EP for serum markers and their ratio among IUP and failed pregnancies including missed abortions MA and EP.
