Table 1 Diagnostic criteria for hemophagocytic lymphohistiocytosis

Diagnosis of HLH is based on the presence of 5 or more of the following:

  • Fever

  • Splenomegaly

  • Cytopenias (affecting 2 of 3 lineages in the peripheral blood)

   Hemoglobin <90 g/L

   Platelets <100 × 10⁹/L

   Neutrophils <1.0 × 10⁹/L

  • Hypertriglyceridemia and/or hypofibrinogenemia

   Fasting triglycerides >3.0 mmol/L (>263 mg/dL)

   Fibrinogen <1.5 g/L

  • Hemophagocytosis in bone marrow, spleen, or lymph nodes

  • Low or absent NK-cell activity

  • Ferritin >500 μg/L

  • Soluble IL-2 receptor >2400 U/mL