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Monocyte Count (Peripheral Blood)

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

This test measures the number of monocytes, a type of white blood cell, in your blood. Monocytes help fight infections and inflammation.

Quick summary

["Monocytes are part of your immune system and help protect your body from illness."]

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

Key facts at a glance

LOINC
71623-3
Short code
Monocytes NFr.DF Snv Manual
Synonyms
Monocytes NFr.DF Snv Manual
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
manual-count
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

What Is a Monocyte Count Used For?

Doctors may order a monocyte count to evaluate immune function, detect infections, or assess conditions like chronic inflammation, certain cancers, or autoimmune diseases. It can also help monitor treatment responses in patients with blood disorders or immune-related illnesses.

How Is This Test Performed?

A small sample of blood is drawn from a vein, usually in your arm. The blood is then analyzed in a lab to count the number of monocytes present.

What Does a Monocyte Count Tell You?

While absolute monocyte counts alone don’t provide a full picture of health, they can indicate whether your immune system is functioning normally or if there may be an underlying issue requiring further investigation.

Common Conditions Monitored

Elevated monocyte counts might suggest chronic infections, certain cancers (like leukemia), or inflammatory conditions. Low counts could be linked to immune deficiencies or certain medications.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

A monocyte count is a key part of a broader assessment when symptoms like persistent fatigue, unexplained fevers, or signs of infection are present. It helps guide treatment decisions but should be interpreted alongside other test results and clinical findings.

Short name

Monocyte Count

Frequently asked questions

Why might my doctor order a monocyte count if I don’t have symptoms?
Your doctor may order this test as part of a routine checkup, to monitor a known condition, or if you’re undergoing treatment for a blood disorder, infection, or inflammatory disease.
What should I expect during or after the blood draw?
You’ll feel a brief pinch when the needle is inserted, but most people tolerate it well. Afterward, you may have a slight bruise or soreness at the site, which usually goes away quickly.
Can I eat or drink before this test?
You can eat and drink normally unless your doctor specifies otherwise. Some tests may require fasting, but this test does not.
  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