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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, two key immune cells. It helps assess your immune response and overall health.

Quick summary

["NLR can give clues about inflammation or infection levels in your body."]

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

Key facts at a glance

LOINC
32800-5
Short code
N men sg C+W135 Ag Spec Ql LA
Synonyms
N men sg C+W135 Ag Spec Ql LA
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
la
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 Is Neutrophil-to-Lymphocyte Ratio (NLR)?

Neutrophils are a type of white blood cell that fight off bacteria and infections. Lymphocytes are another type that help your immune system respond to viruses and other threats. The NLR compares these two cell counts. A higher ratio may suggest inflammation, infection, or certain health conditions, while a lower ratio might indicate a stronger immune response to chronic conditions like autoimmune diseases.

Why Might You Need This Test?

Your doctor may order this test to evaluate immune function, check for infections, monitor chronic illnesses (such as cancer or autoimmune disorders), or assess recovery from illness or surgery.

How Is the Test Performed?

A small blood sample is drawn from your arm. The blood is sent to a lab, where it is analyzed to count neutrophils and lymphocytes. The NLR is then calculated as the ratio of neutrophils to lymphocytes.

What Does a High or Low NLR Mean?

A high NLR could indicate acute infection, inflammation, or conditions like sepsis, while a low NLR might suggest chronic immune activation or certain immune disorders. However, individual results depend on your overall health and medical history.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: NLR in Healthcare

Short name

NLR (Serum/Plasma)

Frequently asked questions

How often will I need this test?
This test is often used as a quick, non-invasive way to monitor health trends, especially in settings like hospitals or during follow-up for chronic conditions. Your doctor will determine how frequently it’s needed based on your specific situation.
What are the normal ranges for this test?
There are no strict universal reference ranges for NLR because it varies widely depending on age, health status, and medical conditions. Your results will be interpreted in relation to your overall health and symptoms.
Can I influence my NLR results?
Yes, lifestyle factors like diet, stress, and exercise can affect white blood cell counts. Avoiding infections, managing chronic conditions, and maintaining good overall health may help keep your NLR in a healthier range.
  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