Figure 5: ROC analysis of citrate and multiple marker metabolites.

(A) The ROC curve of citrate showing the ability as a discriminator of a thyroid nodule. (B) Multiple ROC curve analysis showing that all the seven metabolites had additive values in discriminating benign thyroid nodules from papillary thyroid carcinomas (PTC). The single most important discriminator was citrate which was more abundant in benign thyroid nodules than in PTC.