The OHI index is highly predictive of mortality in patients with lymphoid or myeloid malignancies. ROC analyses for sCD25 and ferritin for predicting HLH-2004 diagnosis (≥5 diagnostic criteria) and mortality prediction in patients with lymphoma (A) and patients with myeloid malignancies (B). The blue arrow indicates the pertinent point on the curve identified as the best balance between sensitivity and specificity (with the highest Youden index). The red arrow indicates the point closest to the OHI values (sCD25 >3900 U/mL and ferritin >1000 ng/mL). (C) Survival of patients with lymphoma (B-cell lymphoma, T-cell lymphoma, and Hodgkin lymphoma; n = 167), classified per the indicated HLH indices. (D) Survival of patients with myeloid malignancies (acute myeloid leukemia, myelodysplastic syndrome, and myeloproliferative neoplasms; n = 48) as in panel C. Classification for this Kaplan-Meier analysis is based on the peak/nadir laboratory values obtained during the initial presentation of HLH/malignancy. The number at risk is presented for each group. Statistics were calculated with the log-rank (Mantel-Cox) test. **P < .001, ***P = .001, ****P < .0001.