Neutrophil-to-Lymphocyte Ratio (NLR) Calculator
Calculate NLR, a simple inflammatory biomarker derived from CBC. Normal NLR is 1-3; elevated NLR (>3) is associated with systemic inflammation, infection severity, and poor outcomes in cancer, sepsis, and cardiovascular disease.
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For informational purposes only — not medical advice. Consult a healthcare professional before acting on results.
NLR (Neutrophil-to-Lymphocyte Ratio) is a simple inflammatory biomarker from routine CBC. Normal NLR is 1-3; elevated NLR (>3) associates with systemic inflammation, infection severity, and poor outcomes in cancer, sepsis, and cardiovascular disease. Formula: NLR = ANC ÷ ALC.
Sources: Clinical hematology, sepsis/cancer prognostic studies.
Key Takeaways
- • NLR 1-3 is normal; >6 suggests significant inflammation
- • NLR >9 associates with higher mortality in sepsis and ICU
- • Derived from routine CBC—no extra cost
- • Interpret with clinical context; not diagnostic alone
Did You Know?
How Does NLR Work?
Neutrophils (Innate)
First responders to infection; rise during bacterial infection and stress.
Lymphocytes (Adaptive)
Decrease during acute stress; relative lymphocytosis may suggest viral etiology.
Ratio Interpretation
Stress and inflammation shift the ratio—elevated NLR reflects this imbalance.
Expert Tips
NLR Interpretation Table
| NLR Range | Category | Clinical Significance |
|---|---|---|
| <1.0 | Low | Lymphocytosis or neutropenia |
| 1.0-3.0 | Normal | Healthy immune balance |
| 3.0-6.0 | Mildly Elevated | Mild inflammation |
| 6.0-9.0 | Moderately Elevated | Significant inflammation |
| >9.0 | Severely Elevated | Critical illness, sepsis consideration |
Frequently Asked Questions
What is the Neutrophil-to-Lymphocyte Ratio (NLR)?
NLR is a biomarker from routine CBC: ANC ÷ ALC. It reflects systemic inflammation and immune balance. Normal NLR is 1-3; elevated NLR (>3) associates with infection severity, cardiovascular risk, and cancer prognosis.
What is a normal NLR range?
NLR 1.0-3.0 is normal. Values above 6 suggest significant inflammation; above 9 may indicate critical illness, sepsis, or poor prognosis in cancer and cardiovascular disease.
When is NLR used clinically?
Sepsis prediction, cardiovascular risk stratification, cancer prognosis, surgical outcomes, and COVID-19 severity assessment. Derived from routine CBC with differential.
How is NLR calculated?
NLR = ANC ÷ ALC. From percentages: ANC = WBC × (Neutrophil%/100), ALC = WBC × (Lymphocyte%/100). Example: WBC 7.5, Neut 55%, Lymph 35% → NLR = 1.57.
What causes elevated NLR?
Bacterial infection, stress, surgery, malignancy, cardiovascular disease, and systemic inflammation. Neutrophils rise and lymphocytes fall during acute stress.
Can NLR predict mortality?
Yes. NLR >9 is associated with higher mortality in sepsis, ICU, and cancer settings. NLR helps stratify risk when combined with clinical context.
Key Statistics
Official Data Sources
⚠️ Disclaimer: This calculator is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. NLR interpretation requires clinical context. Always consult a qualified healthcare provider.
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