Skip to content

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' neutrophil count to your lymphocyte count in your blood. Neutrophils and lymphocytes are types of white blood cells that help fight infections.

Quick summary

["NLR helps doctors assess your immune response and overall health, especially in conditions like inflammation or infection."]

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

Key facts at a glance

LOINC
91803-7
Short code
N men DNA Upper resp Ql NAA+probe
Synonyms
N men DNA Upper resp Ql NAA+probe
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
probe-amp-tar
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?

The test looks at two key types of white blood cells: neutrophils and lymphocytes. Neutrophils are often the first responders to infections, while lymphocytes play a role in long-term immunity. The NLR compares their numbers to give a snapshot of your immune system’s balance.

Why Might You Need This Test?

Doctors may order this test to evaluate conditions like infections, inflammation, or certain cancers. It can also help monitor how your body responds to treatments or track chronic health issues.

How Is This Test Performed?

A small blood sample is drawn from your arm. The sample is then analyzed in a lab to count the neutrophils and lymphocytes, and the ratio is calculated.

What Are Common Uses?

NLR is often used in settings like hospital care to guide decisions about treatments, such as antibiotics or cancer therapies. It may also help track recovery or disease progression in certain conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

NLR (Serum/Plasma)

Frequently asked questions

What Does an Elevated NLR Mean?
An elevated NLR could signal an active infection, inflammation, or other health concerns. Your doctor will interpret results in the context of your medical history and symptoms.
How Often Should I Get This Test?
Frequency depends on your health needs. Your doctor will determine how often to check NLR based on your condition, treatment plan, or ongoing monitoring requirements.
Can I Influence My NLR Results?
While you can’t directly control NLR, lifestyle factors like diet, stress, and exercise may indirectly affect immune function. Always follow your doctor’s advice for managing your health.
  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