HLH-2004 Diagnostic Criteria (5 of 8)

Applies the HLH-2004 criteria for haemophagocytic lymphohistiocytosis, counting how many of eight clinical/laboratory criteria are met to establish the diagnosis when ≥ 5 of 8 are satisfied; a molecular diagnosis consistent with HLH also establishes it.

Criterion 1 — Fever > 38.5 °C

Criterion 2 — Splenomegaly

Neonate < 4 weeks old? (sets the haemoglobin cytopenia cutoff)

Criterion 3 — Haemoglobin (g/dL)

Criterion 3 — Platelets (×10&sup9;/L)

Criterion 3 — Absolute neutrophil count (×10&sup9;/L)

Criterion 4 — Fasting triglycerides (mg/dL; leave blank if not measured)

Criterion 4 — Fibrinogen (mg/dL; leave blank if not measured)

Criterion 5 — Haemophagocytosis on histopathology

Criterion 6 — NK-cell activity

Criterion 7 — Serum ferritin (ng/mL)

Criterion 8 — Soluble CD25 / soluble IL-2 receptor alpha (U/mL)