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Neutrophil-to-Lymphocyte Ratio (NLR) from Whole Blood

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

This test measures the ratio of your blood’s neutrophils (a type of white blood cell) to lymphocytes (another type of white blood cell). It helps assess your immune response and overall health.

Quick summary

["NLR helps doctors evaluate inflammation and immune activity in your blood."]

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

Key facts at a glance

LOINC
44704-5
Short code
NEB gene Mut Anl Bld/T
Synonyms
NEB gene Mut Anl Bld/T
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
molgen
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What Is Neutrophil-to-Lymphocyte Ratio Used For?

Doctors may use NLR to monitor conditions like infections, inflammation, or certain cancers. It can also help track how your body responds to treatments, such as chemotherapy or steroids.

How Is This Test Performed?

A small blood sample is drawn from your arm. The test measures the counts of neutrophils and lymphocytes in your whole blood and calculates their ratio.

When Might You Need This Test?

Your doctor may order this test if you have symptoms like fever, fatigue, or unexplained weight loss, or if you’re undergoing treatment for a condition affecting your immune system.

What Do the Results Mean?

Higher NLR may suggest inflammation or infection, while lower NLR could indicate immune suppression. Your doctor will interpret results in the context of your overall health and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Neutrophil-to-Lymphocyte Ratio is often used as a quick, non-invasive marker to guide treatment decisions, especially in acute settings like infections or cancer care. It complements other tests but isn’t a standalone diagnosis.

Short name

NLR (Whole Blood)

Frequently asked questions

Why was I asked to have this test?
Your doctor may have recommended it to check for inflammation, infection, or immune-related conditions. It helps monitor how your body is responding to treatments or symptoms you’re experiencing.
Can I eat or drink before this test?
No special preparation is needed. You can eat and drink normally, but avoid smoking or heavy exercise right before your blood draw.
Will this test hurt?
The blood draw may cause a slight sting, but it usually doesn’t cause significant discomfort. Most people feel relief shortly after.
  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