Table 1 The diagnostic criteria for hemophagocytic lymphohistiocytosis with definitions
Findings | Definitions | Present |
|---|---|---|
Fever | Peak temperature of > 38.5 °C for > 7 days | X |
Splenomegaly | Spleen palpable > 3 cm below costal margin | X |
Cytopenia | Involving > 2 cell lines; Hb < 9.0 g/dL, ANC < 1.0 × 109/L, platelets < 100 × 109/L | X |
Hypertriglyceridemia or hypofibrinogenemia | Fasting triglycerides > 2.0 mmol/L or > 3 SD more than normal value for age or fibrinogen < 1.5 g/L or > 3 SD less than normal value for age | X |
Hemophagocytosis | Hemophagocytosis demonstrated in biopsy samples of bone marrow, spleen or lymph nodes | X |
Low or absent NK cell activity | Reduced NK cell activity as measured by standardized assay | |
Hyperferritinemia | Serum ferritin > 500 ng/mL | X |
Elevated soluble interleukin-2 (CD25) levels | CD25 level > 2400 U/mL | X |