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Monocyte count (per microliter of 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 in your body.

Quick summary

["Monocytes help protect your immune system and respond to infections or injury."]

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

Key facts at a glance

LOINC
40521-7
Short code
Monocytes NFr Plr Manual
Synonyms
Monocytes NFr Plr 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

Why Is This Test Done?

Doctors may order a monocyte count to diagnose or monitor conditions like infections, certain cancers (such as leukemia), autoimmune diseases, or to check for signs of inflammation in your body. It can also help evaluate how well your immune system is functioning.

What to Expect Before the Test

No special preparation is needed for this test. A simple blood draw is performed in a clinic or lab. The blood sample is analyzed to count the monocytes.

How the Test Works

Blood is drawn from a vein, usually in your arm. The sample is then processed to count the number of monocytes, measured in cells per microliter of blood.

Possible Results and Interpretation

Results are compared to standard ranges for healthy individuals. High or low monocyte counts may signal underlying health issues that need further evaluation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Monocyte level

Frequently asked questions

What does a high or low monocyte count mean?
A high monocyte count could mean you have an ongoing infection, an inflammatory condition, or a blood-related disorder. A low count might suggest immune suppression, medication side effects, or a bone marrow issue. Your doctor will discuss these findings with you.
How often should I get this test?
Your doctor will determine the frequency based on your medical history, symptoms, and treatment plan. Regular monitoring may be needed if you have a chronic condition or are undergoing treatment for a blood disorder.
Can I eat or drink before this test?
You can eat and drink normally before this test, as no special preparation is required. However, always follow your doctor’s instructions for any specific instructions related to your health condition.
  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