🦠 Systemic Immune-Inflammation Index (SII)
Calculate the Systemic Immune-Inflammation Index (SII) from the blood count.
Systemic Immune-Inflammation Index (SII)
Platelets (×10⁹/L)
Absolute neutrophils (×10⁹/L)
Absolute lymphocytes (×10⁹/L)
When to use
Research-oriented prognostic inflammatory marker, mainly in oncology.
How it works
SII = platelets × neutrophils ÷ lymphocytes (absolute counts).
Key points
- Higher SII linked to worse prognosis in several cancers.
- Thresholds (~500–900) are study-specific.
- Not a standalone clinical decision tool.
References
Decision support for licensed clinicians only; not a substitute for clinical judgement, diagnosis or local protocols.