Fig. 2. Receiver operating characteristics (ROC) curve of the multivariate model to predict pathologically damaged sperm DNA, and included straightness (STR), beat-cross frequency (BCF), percentage of progressive motile sperm cells (PPMS), and vitality. The addition of STR, BCF, PPMS to vitality yields an area under the ROC curve (AUROC) of 91.5% (95% confidence interval, 85.7%–97.2%), a sensitivity of 85.2%, and a specificity of 86.3%.