[Application of ROC curve for evaluation of the effect of prenatal screening during second trimester of pregnancy].

Objective: To develop a method for evaluating the feasibility of prenatal screening using local median value and determining the cut-off value.

Methods: With receiver operating characteristic curve (ROC) analysis, results of second trimester prenatal screening calculated by a local median value in a new model and the built-in median value in 2T software were compared. The cut-off value was set by serial analysis of true and false positive rates and other relevant data.