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Neutrophil Segment Count in Peripheral Blood

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

This test measures the number of segmented neutrophils, a type of white blood cell, in your blood. Neutrophils are key to fighting infections.

Quick summary

["A neutrophil count helps assess your immune response and risk of infection."]

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

Key facts at a glance

LOINC
33384-9
Short code
Neuts Seg NFr Prt
Synonyms
Neuts Seg NFr Prt
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
86592
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 a Neutrophil?

Neutrophils are a type of white blood cell that play a central role in your body’s immune defense. They are called 'segmented' because their nucleus has multiple lobes when viewed under a microscope. These cells are the most abundant type of white blood cell and are the first responders to infection or inflammation.

Why Might You Need This Test?

Your doctor may order this test to evaluate your immune system, diagnose infections (such as bacterial infections), or check for conditions like neutropenia (low neutrophil count) or overactive immune responses.

How Is This Test Done?

A small sample of your blood is drawn from a vein, usually in your arm. The sample is then analyzed in a lab to count the segmented neutrophils among your total white blood cells.

What Do Results Mean?

Results are typically expressed as a count of segmented neutrophils per microliter (µL) of blood. While reference ranges vary by lab, lower than expected counts may indicate immune suppression, while higher counts can signal infection or inflammation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Neutrophils are crucial for fighting bacterial infections. Low neutrophil counts can increase susceptibility to infections, especially in people with weakened immune systems. High counts may suggest an active infection or inflammatory process. Your doctor will interpret results in the context of your symptoms and overall health.

Short name

Neutrophil Count (Segmented)

Frequently asked questions

What causes low neutrophil counts?
Low neutrophil counts (neutropenia) can result from medications, certain cancers, autoimmune diseases, or genetic disorders. Chronic conditions like leukemia or severe infections may also reduce neutrophil production.
What are common symptoms of abnormal neutrophil counts?
Symptoms of low neutrophils include frequent or severe infections, fatigue, and fever. High neutrophil counts may cause fever, rapid heartbeat, or swollen glands, though these are less common.
Can lifestyle changes affect neutrophil counts?
Yes, stress, poor sleep, and certain medications (like chemotherapy or steroids) can temporarily lower neutrophil counts. Maintaining good nutrition and reducing stress may support immune function, but this test is not affected by lifestyle alone.
  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