The diagnostic accuracy of maternal serum alpha-fetoprotein variants (AFP-L2 and AFP-L3) in predicting fetal open neural tube defects and abdominal wall defects.

INTRODUCTION

To evaluate a risk model of the maternal serum α-fetoprotein variants L2 and L3 (AFP-L2 and AFP-L3) for predicting fetal open neural tube defects (ONTD) and abdominal wall defects (AWD).

METHODS

Subjects were divided into the ONTD group (21), the AWD group (16) and the control group (38). Comparative analysis was performed using a risk model, receiver operating characteristic (ROC) curves and area under the curve (AUC) were used for screening performance of AFP-L2 and AFP-L3.

RESULTS

AFP-L2 and AFP-L3 concentrations in the ONTD group and the AWD group were both significantly higher than those in the control group (P < 0.001). The AUC for screening ONTD or AWD using AFP-L2 was 0.830 [95% confidence interval (CI):0.734-0.926, P < 0.001], while using AFP-L3 was 0.886 (95% CI: 0.809-0.963, P < 0.001). ROC curves indicated that the optimal threshold values for ONTD or AWD by AFP-L2 and AFP-L3 were 1.467 multiple of the median (MoM) and 1.944 MoM. The corresponding sensitivity, specificity and Youden index for AFP-L2 and AFP-L3 were 0.703, 0.947, 0.650 and 0.730, 0.974, 0.703, respectively.

CONCLUSION

AFP-L2 and AFP-L3 are favorable biomarkers for screening ONTD and AWD fetuses, and the risk model using AFP-L2 and AFP-L3 is of superior sensitivity and specificity.