Systemic Inflammation Response Index: Clinical Guide

Clinical guide to Systemic Inflammation Response Index including formula, assumptions, units, interpretation, limitations and references.

Calculates the systemic inflammation response index from neutrophils, monocytes and lymphocytes.

Overview

Calculates the systemic inflammation response index from neutrophils, monocytes and lymphocytes.

Clinical Significance

A composite inflammatory index studied in cancer and critical illness. Published thresholds differ by cohort.

How It Is Calculated

  • SIRI = neutrophils × monocytes / lymphocytes.

Interpretation

  • A composite inflammatory index studied in cancer and critical illness. Published thresholds differ by cohort.

Worked Example

Enter a clinically consistent set of values in the displayed units. MedicalC applies: SIRI = neutrophils × monocytes / lymphocytes.

Limitations

  • This tool does not establish a diagnosis or mandate treatment.
  • Published cut-offs may vary between cohorts and measurement methods.
  • Calculation precision cannot compensate for poor source data.

Clinical Pearls

  • Trend the result over time where clinically appropriate.
  • Record the source values and units alongside the calculated result.

Common Mistakes

  • Using the wrong unit.
  • Combining measurements obtained at different times.
  • Applying a research-derived threshold as a universal treatment trigger.

Frequently Asked Questions

What does this calculator provide?

Calculates the systemic inflammation response index from neutrophils, monocytes and lymphocytes.

Can this result be used alone?

No. It must be interpreted with clinical context and appropriate investigations.

What equation is used?

SIRI = neutrophils × monocytes / lymphocytes.

What is the main limitation?

The result depends on valid inputs and may not be calibrated for every population or setting.

References

  1. Qi Q et al. A novel systemic inflammation response index predicts survival in advanced pancreatic cancer. Cancer. 2016. — Formula, physiological or validation reference.

Reviewed by: MedicalC Clinical Editorial Team
Last reviewed: July 2026

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