Table 2. HLH Clinical Diagnostic Criteria^*.

Five of the eight following criteria:
1. Fever ≥38.5ºC
2. Splenomegaly
3. Cytopenias affecting 2 of the 3 lineages in the peripheral blood
Hemoglobin < 9 g/dL
Platelets < 100 x 103/mL
Neutrophils < 1 x 103/mL
4. Hypertriglyceridemia (fasting, >265 mg/dL) and or hypofibrinogenemia  (<150 mg/dL)
5. Hemophagocytosis in bone marrow, spleen, lymph nodes, or liver
6. No or absent natural killer cell activity
7. Ferritin > 500 ng/mL
8. Elevated sCD25 (α-chain of sIL-2 receptor)

^*Adapted from Jordan et al (3).