Table 1. . Patient requires greater than or equal to 5 of 8 diagnostic criteria.

Diagnostic criteria
1. Fever†	Temperature >38.5°C for >7 days
2. Splenomegaly†	Spleen tip palpated >3 cm below left costal margin
3. Cytopenia:	≥2 lineages
Hemoglobin†	<90 g/l (neonates <100 g/l)
Platelets†	<100 × 109/l
Neutrophil†	<1 × 109/l
4. Hyperferritinemia†	>500 μg/l
5. Hypofibrinogenemia† or hypertriglyceridemia†	<1.5 g/l, or >3 mmol/l
6. Elevated soluble CD25†	>2400 U/ml
7. Hemophagocytosis	Bone marrow, spleen, liver, lymph node or other tissues
8. Reduced or absent NK cytotoxicity
Supportive evidence
Elevated transaminases and bilirubin†
Elevated lactate dehydrogenase†
Elevated d-dimers†
Elevated cerebrospinal fluid cells and/or protein

Criteria for the diagnosis of hemophagocytic lymphohistiocytosis based on the HLH-2004 diagnostic and therapeutic guidelines [7].

^†Present in our patient.