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Neutrophil-to-Lymphocyte Ratio (NLR) in serum/plasma

Published: August 9, 2026Updated: August 16, 2026

This test measures the ratio of your white blood cells’ neutrophils to lymphocytes, a simple blood count comparison that can help assess inflammation or immune response.

Quick summary

["NLR helps doctors gauge inflammation or infection risk based on your blood cells."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
39925-3
Short code
NM Hrt Gated+WM+EF Rest+W RNC IV
Synonyms
NM Hrt Gated+WM+EF Rest+W RNC IV
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
nm
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Does This Test Measure?

Neutrophils are a type of white blood cell that fight infections, while lymphocytes help your immune system respond to viruses and chronic conditions. The NLR compares these two cell types by dividing neutrophils by lymphocytes. A higher ratio may suggest inflammation, infection, or certain cancers, while a lower ratio might indicate immune suppression or other conditions.

Why Might You Need This Test?

Your doctor may order an NLR test to monitor conditions like infections, autoimmune diseases, cancer, or to check how your body is responding to treatment. It’s also sometimes used before surgery or during recovery to assess risk.

How Is the Test Performed?

A small blood sample is drawn from your arm, and the cells are analyzed in a lab. The NLR is calculated automatically from the count of neutrophils and lymphocytes in your blood.

What Do the Results Mean?

Results aren’t given in a single range because NLR varies widely depending on health, age, and medical conditions. Instead, doctors compare your NLR to your own baseline or to what’s typical for your situation (e.g., pre-existing illness).

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

NLR (Serum/Plasma)

Frequently asked questions

Why is this test important?
NLR can signal inflammation, infection, or immune dysfunction, helping doctors diagnose or guide treatment for conditions like sepsis, cancer, or chronic diseases. It’s also useful for monitoring treatment progress or adjusting care plans.
What are common reasons for this test?
Common reasons include evaluating infection risk before surgery, assessing chronic diseases (e.g., arthritis, heart disease), or monitoring cancer treatment side effects. It’s sometimes used alongside other blood tests for a fuller picture.
How soon will I get results?
Results are typically available within 1–3 business days, depending on your lab. Your doctor will discuss them with you during your follow-up visit.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy