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Neutrophil-to-lymphocyte ratio (NLR) calculated from whole blood cell counts

Published: August 9, 2026Updated: August 17, 2026

This test measures the ratio of neutrophils to lymphocytes in your blood, which can help assess immune response and inflammation.

Quick summary

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

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
33577-8
Short code
RF IgM Titr Ser Neph
Synonyms
RF IgM Titr Ser Neph
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
7.35
Ref high
7.45
Critical range
7.2 N/A – 7.6 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
nephelometry
CPT
86430
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 infections, while lymphocytes are another type involved in immune defense. NLR compares these two cell types. A higher ratio may suggest inflammation or infection, while a lower ratio might indicate immune suppression or certain conditions like chronic inflammation or cancer.

Why Is This Test Done?

Your healthcare provider may order NLR testing to monitor conditions like infections, autoimmune diseases, or cancer. It can also help assess response to treatments or evaluate overall immune status.

How Is This Test Performed?

This is a calculated test based on results from a complete blood count (CBC). Blood is drawn from a vein, and a machine analyzes the different types of white blood cells to determine the ratio.

What Do Results Mean?

Results are expressed as a ratio (e.g., 2.5:1). While specific reference ranges vary by lab, higher NLR values often correlate with increased inflammation or infection risk, while lower values may suggest immune suppression or other conditions.

Reference range

NCBI: pH 7.35-7.45N/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Frequently asked questions

What are the possible causes of abnormal NLR?
Abnormal NLR can result from infections (like bacterial or viral), inflammatory conditions (such as rheumatoid arthritis or sepsis), certain cancers, or immune system disorders. Chronic conditions like diabetes or kidney disease may also affect NLR. Your provider will consider your full medical history and other test results to interpret results accurately.
How often should I get this test?
The frequency depends on your health condition and treatment plan. If you have a chronic illness, your doctor may order NLR testing periodically to monitor changes in your immune status or response to treatment. Follow your healthcare provider’s recommendations.
Does this test have any risks or side effects?
Blood draws are generally safe but may cause mild discomfort or bruising at the site. Rarely, there may be a slight reaction or infection at the needle site. If you experience excessive bleeding or pain, contact your provider immediately.
  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 17, 2026. · Read our editorial policy