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Neutrophil Segment Count (in Blood)

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

This test measures the proportion or absolute number of neutrophils, a type of white blood cell, in your blood. Neutrophils help fight infections by attacking bacteria and other invaders.

Quick summary

["Neutrophils are key defenders against infections and can indicate inflammation or infection status."]

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

Key facts at a glance

LOINC
11128-6
Short code
Neuts Seg NFr Mar
Synonyms
Neuts Seg NFr Mar
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Neutrophils Do in Your Body

Neutrophils are the most common type of white blood cell in your bloodstream. They play a critical role in your immune response by identifying and destroying bacteria and other harmful pathogens. When your body detects an infection or inflammation, neutrophils rush to the site to help neutralize the threat. This test helps doctors assess whether your immune system is responding appropriately to infections or other conditions that might affect neutrophil levels.

Why Your Doctor Might Order This Test

Your doctor may order this test if you have symptoms like frequent infections, unexplained fevers, or signs of inflammation. It can also be used to monitor conditions such as certain blood disorders, autoimmune diseases, or after treatments that might affect your immune system, like chemotherapy or certain medications.

When to Expect Results

Results from this test are typically available within 1 to 3 business days, depending on your lab’s processing time. Your healthcare provider will discuss the results with you and explain any changes needed to your treatment plan.

Common Conditions Affecting Neutrophil Levels

Low neutrophil counts (neutropenia) may occur due to infections, certain medications, blood disorders, or autoimmune diseases. High neutrophil counts (neutrophilia) can be seen with infections, inflammation, or stress. Chronic conditions like leukemia or certain cancers may also influence neutrophil levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Neutrophil Percentage or Absolute Count

Frequently asked questions

How is this test typically collected?
This test is usually done by drawing a small amount of blood from a vein in your arm. A healthcare professional will clean the area with an antiseptic, insert a needle, and collect the blood into a tube. The blood sample is then sent to a lab for analysis.
What preparation is needed before this test?
No special preparation is usually required for this test. However, if you are taking certain medications that might affect your white blood cells, let your doctor know before the test. Avoiding strenuous activity or eating heavy meals right before the test may help ensure accurate results, but this depends on the lab’s specific instructions.
Are there any risks or side effects associated with this test?
The most common side effect is a slight bruise, redness, or minor pain at the injection site. Rarely, you might experience swelling or a small lump. If you experience excessive bleeding, severe pain, or signs of infection (like fever or redness spreading from the site), contact your healthcare 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 16, 2026. · Read our editorial policy