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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 key immune cells that protect your body from illness and injury."]

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

Key facts at a glance

LOINC
71672-0
Short code
Monocytes NFr.DF Bld Manual
Synonyms
Monocytes NFr.DF Bld Manual
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
manual-count
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What Is a Monocyte Count Used For?

A monocyte count helps doctors assess your immune system’s health, especially when monitoring conditions like chronic infections, autoimmune diseases, or certain cancers. It may also be checked if you have symptoms like frequent infections, unexplained fevers, or swelling.

How Is This Test Done?

A small blood sample is taken from a vein in your arm. The blood is then analyzed in a lab to count your monocytes. This test is usually done as part of a routine blood test or when additional immune system details are needed.

When Might You Need This Test?

Your doctor may order a monocyte count if you have symptoms like persistent infections, unexplained weight loss, fatigue, or if you’re being treated for conditions like leukemia, lymphoma, or other immune-related disorders.

What Do the Results Mean?

Results are compared to a general reference range for healthy adults. High or low monocyte counts may signal underlying health issues that need further evaluation by your healthcare provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Monocyte Count

Frequently asked questions

Why might my doctor want to check my monocyte count?
Your doctor may check it to monitor immune function, diagnose conditions like infections or autoimmune diseases, or evaluate treatment responses for blood-related disorders.
What are the common reference ranges for monocyte counts?
Reference ranges vary by lab and age. Typically, healthy adults have monocyte counts between 0.05% and 0.1% of total white blood cells, but exact values depend on your blood sample and lab methods.
Can I prepare for this test in any special way?
No special preparation is needed. You can eat, drink, and go about your normal activities, but avoid heavy exercise just before the blood draw if advised by your doctor.
  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