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Monocyte Count in Whole 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 respond to inflammation.

Quick summary

["Monocytes are important for immune defense and inflammation response."]

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

Key facts at a glance

LOINC
101148-5
Short code
MO1/Monocytes NFr Bld
Synonyms
MO1/Monocytes NFr Bld
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 health, especially when monitoring conditions like infections, autoimmune diseases, or certain cancers. It may also be checked during chemotherapy or other treatments that affect white blood cell counts.

When Might You Need This Test?

Your doctor may order a monocyte count if you have symptoms like fever, fatigue, or unexplained weight loss, or if you’re undergoing treatment that could lower your white blood cell count. It’s also part of routine blood work for certain health conditions.

How Is the Test Done?

A small blood sample is taken from a vein, usually in your arm. The sample is sent to a lab where it’s analyzed to count your monocytes. This is a quick and painless procedure.

What Do Results Mean?

Results are compared to a general reference range for healthy adults. Low or high counts may signal underlying health issues, but your doctor will interpret results in the context of your overall health and symptoms.

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 order this test to monitor your immune system, especially if you have symptoms like frequent infections, fatigue, or if you’re receiving treatments that could affect white blood cells.
What are the normal ranges for monocyte counts?
There’s no single range for everyone—results depend on your health and lab standards. Your doctor will share what’s normal for you based on your test results.
Can I eat or drink anything before this test?
No special preparation is needed for this test. However, always follow your doctor’s instructions for fasting or other dietary restrictions if applicable to other blood tests you may have.
  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