| Criteria | Patient Characteristics |
| Fever | Yes |
| Splenomegaly | Yes |
| Cytopenia (affecting ≥2 of 3 lineages) | Yes |
| Hypertriglyceridemia and/or hypofibrinogenemia | Yes |
| Histopathological criteria | Yes |
| Low or absent NK cell activity | Not Applicable |
| Ferritin ≥500 micrograms/L | Yes |
| Soluble CD 25 ≥ 2400 U/ml | Not Applicable |
| Molecular Diagnosis | Not Applicable |