Table 1.
Selected MAS and HLH classification criteria*
| fHLH26 | Adult HScore27 | MAS-sJIA10 | |
|---|---|---|---|
| Clinical | |||
| Fever | Present | <38·4 (0); 38·4–39·4 (33); >39·4 (49) | Present |
| Hepatomegaly | Not included | Included (as below) | Not included |
| Splenomegaly | Present | Neither (0); either hepatomegaly or splenomegaly (23); both (38) | Not included |
| Immunosuppression | Not included | No (0); yes (18) | Not included |
| Laboratory | |||
| Cytopenias >2 lineages | Either: haemoglobin <90 g/L, platelets <100 × 109/L, or neutrophils <1 × 109/L | One lineage (0), two lineages (24), or three lineages (34) | Not included |
| Platelets | Included in cytopenia criteria | Included in cytopenia criteria | ≤181 × 109/L |
| Ferritin, ng/mL | ≥500 | <2000 (0); 2000–6000 (35); >6000 (50) | >684 |
| Hypertriglyceridaemia, mmol | ≥3 | <1·5 (0); 1·5–4 (44); >4 (64) | >1·76 |
| Hypofibrinogenaemia, g/L | ≤1·5 | >2·5 (0); <2·5 (30) | ≤3·6 |
| Liver function tests, IU/L | Not included | AST<30 (0); >30 (19) | AST>48 |
| Low or absent natural killer cell activity | Present | Not included | Not included |
| Soluble CD25, U/mL | ≥2400 | Not included | Not included |
| Tissue | |||
| Haemophagocytosis | Present | No (0), yes (35) | Present |
| Fulfilment of criteria | |||
| Interpretation | Molecular diagnosis consistent with fHLH or ≥5 of 8 criteria | Produces a probability outcome; scores >169 are 93% sensitive and 86% specific for HLH | Febrile patient with known or suspected sJIA, ferritin >684 ng/mL and ≥2 additional items |