Fig. 2.

ROC curves for all patients (HLH, CCS, and AOSD). (A) ROC curve for CRP alone demonstrates an AUC of 0.845, indicating a good diagnostic performance in diagnosing HLH, with a sensitivity of 90.9% and a specificity of 66.7% for CRP values less than 130 mg/L, as calculated by Youden’s index. (B) The addition of CRP to ferritin improves the AUC from 0.842 to 0.927 with an increased sensitivity of 90.9% (improved from 63.6% for ferritin alone) and a specificity of 85.2% (88.9% with ferritin alone). (C) The addition of CRP to HScore improves the AUC from 0.894 to 0.954 and results in an increased sensitivity of 88.6% (from 84.1% for HScore alone) and increased specificity from 85.2–92.6%.