Figure 3. The development of an integrated model for the differentiation of COVID-19 from other respiratory diseases in the training set. (A) ROC curve for the performance of first RT-PCR; (B) ROC curve for the performance of CT; (C) ROC curve for the integrated model. The integrated model contained the results of the first RT-PCR, CT, and LYP in the blood. (D) The cross-validation of the integrated model using the permutation test (1000 times). ROC curve: Receiver operator characteristic curve; LYP: lymphocyte percentage.