Table 1.

At least five of the eight criteria must be present for a diagnosis to be established.

Diagnostic Criteria for Hemophagocytic Lymphohistiocytosis
Criterion	Present in This Patient
Fever (Temperature >38.5C for >7 days)	Yes
Splenomegaly	Yes
Cytopenias involving 2 or more lines	Yes
Hypertriglyceridemia and/or hypofibrinogenemia (fasting triglyceride levels >3 mmoL/liter; fibrinogen <1.5g/liter)	Yes (hypofibrinogenemia)
Ferritin level >500mcg/L	Yes
Soluble CD25 level>2400 U/mL	No
Decreased or absent natural killer cell activity	Not measured
Hemophagocytosis in bone marrow, central nervous system, or lymph nodes	Yes