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Monocyte count (per microliter of whole blood)

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

This test measures the number of monocytes, a type of white blood cell that helps fight infections and inflammation.

Quick summary

["Monocytes are part of your immune system and can help identify infections or immune-related conditions."]

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

Key facts at a glance

LOINC
71677-9
Short code
Monocytes NFr.DF Bld Auto
Synonyms
Monocytes NFr.DF Bld Auto
Category
chemistry
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
automated-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 Are Monocytes?

Monocytes are a type of white blood cell produced by your bone marrow. They circulate in your bloodstream and move into tissues to help fight infections, remove dead cells, and regulate inflammation. When your body detects an infection or injury, monocyte levels may temporarily rise or change.

Why Might This Test Be Done?

Doctors may order a monocyte count to check for infections, autoimmune diseases, or other conditions affecting your immune system. It can also help monitor certain treatments or conditions like leukemia or chronic inflammation.

How Is the Test Performed?

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 number of monocytes present in your blood.

What Do Results Mean?

Results are typically reported as the number of monocytes per microliter of blood. While specific reference ranges vary by lab, elevated or low monocyte counts may signal underlying health concerns that need further evaluation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

High monocyte counts may indicate chronic infections, certain cancers, or inflammatory diseases. Low monocyte counts can suggest immune deficiencies, severe infections, or conditions affecting bone marrow function. Always discuss results with your healthcare provider for personalized interpretation.

Short name

Monocyte count

Frequently asked questions

What Causes Changes in Monocyte Levels?
Changes in monocyte levels can be caused by infections (like tuberculosis or fungal infections), autoimmune diseases (such as rheumatoid arthritis), certain cancers (like leukemia), or medications that affect the immune system.
How Often Should I Get This Test?
The frequency of this test depends on your medical condition and treatment plan. Your doctor will determine if and how often you need monitoring based on your health needs.
Can I Prepare for This Test?
No special preparation is usually needed. However, inform your doctor about any medications you’re taking, as some may affect blood test results.
  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