🧬 HScore (Hemophagocytic Syndrome/HLH Probability)
The HScore estimates the probability of secondary (reactive) hemophagocytic lymphohistiocytosis (HLH) from nine weighted clinical, laboratory, and cytological items.
HScore (Hemophagocytic Syndrome/HLH Probability)
Known immunosuppression (HIV/long-term immunosuppressants)
Temperature (°C)
Organomegaly
Cytopenic lineages (Hb≤9.2/WBC≤5000/PLT≤110k)
Ferritin (ng/mL)
Triglycerides (mmol/L)
Fibrinogen (g/L)
AST (U/L)
Hemophagocytosis on bone marrow
When to use
Enter temperature, ferritin, triglycerides, fibrinogen and AST, and select immunosuppression status, organomegaly, number of cytopenic lineages, and marrow hemophagocytosis; the tool returns a 0–337 score and probability band.
How it works
Weighted sum of nine items (immunosuppression 18; temperature ≤38.4 = 0 / 38.4–39.4 = 33 / >39.4 = 49; organomegaly 0/23/38; cytopenias 0/24/34; ferritin <2000 = 0 / 2000–6000 = 35 / >6000 = 50; triglycerides <1.5 = 0 / 1.5–4 = 44 / >4 = 64; fibrinogen ≤2.5 g/L = 30; AST ≥30 = 19; marrow hemophagocytosis 35). A cutoff ≈169 maximizes accuracy.
Key points
- A cutoff around 169 gives roughly 82% sensitivity and 88% specificity for reactive HLH, while a score above 250 corresponds to >99% probability and below 90 to low probability (original synthesis · not guideline verbatim).
- Sepsis, severe infection, and other hyperinflammatory states overlap with HLH, so the score complements rather than replaces sIL-2R, NK-cell activity, marrow review, and identification of the trigger.
- Ferritin and triglycerides carry the most weight, so trending these values can support an evolving diagnosis when the initial score is intermediate.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.