🦠 Systemic Immune-Inflammation Index (SII)
Calculate the Systemic Immune-Inflammation Index (SII) from the blood count.
Clinical takeaway
Higher SII linked to worse prognosis in several cancers.
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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.
Worked calculation
The values below come from this tool's own example placeholders and are computed server-side with the formula shown on this page, so the arithmetic can be checked quickly. It demonstrates how to substitute values only — it is not clinical advice and not a real case.
| Platelets | 250 ×10⁹/L |
|---|---|
| Absolute neutrophils | 6.0 ×10⁹/L |
| Absolute lymphocytes | 2.0 ×10⁹/L |
→SII750×10⁹/L
- Formula：platelets × neutrophils / lymphocytes
- Note：Higher SII has been associated with worse prognosis in several cancers; thresholds (~500–900) are study-specific.
Frequently asked questions
- What is Systemic Immune-Inflammation Index (SII)?
- Calculate the Systemic Immune-Inflammation Index (SII) from the blood count.
- How is Systemic Immune-Inflammation Index (SII) calculated? What is the core formula?
- SII = platelets × neutrophils ÷ lymphocytes (absolute counts).
- When is Systemic Immune-Inflammation Index (SII) used?
- Research-oriented prognostic inflammatory marker, mainly in oncology.
- What are the key clinical points for Systemic Immune-Inflammation Index (SII)?
- Higher SII linked to worse prognosis in several cancers. Thresholds (~500–900) are study-specific. Not a standalone clinical decision tool.
- What are the limits and cautions when using Systemic Immune-Inflammation Index (SII)?
- For licensed clinicians and clinical researchers. Interpret results with history, investigations and local protocols; not a diagnosis or prescription, and not a substitute for multidisciplinary decision-making or local guidelines.
- How is Systemic Immune-Inflammation Index (SII) calculated in practice? Can you show a worked example?
- Inputs: Platelets 250 ×10⁹/L, Absolute neutrophils 6.0 ×10⁹/L, Absolute lymphocytes 2.0 ×10⁹/L → Result: SII 750 ×10⁹/L（Formula: platelets × neutrophils / lymphocytes, Note: Higher SII has been associated with worse prognosis in several cancers; thresholds (~500–900) are study-specific.）