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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 your body fight infections and respond to inflammation.

Quick summary

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

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

Key facts at a glance

LOINC
33362-5
Short code
Monocytes NFr Plr
Synonyms
Monocytes NFr Plr
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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?

Monocytes are a type of white blood cell that plays a key role in your body’s immune response. They help identify and destroy pathogens like bacteria and viruses, as well as damaged cells. Your doctor may order this test to monitor your immune system, check for infections, or evaluate conditions like chronic inflammation or certain blood disorders.

Why Might Your Doctor Order This Test?

A doctor may recommend a monocyte count test if you have symptoms like frequent infections, unexplained fevers, fatigue, or signs of inflammation. It’s also used in diagnosing or monitoring conditions such as leukemia, autoimmune diseases, or infections like tuberculosis.

How Is the Test Performed?

This test involves drawing a small amount of blood from a vein, usually in your arm. The blood sample is then analyzed in a lab to count the number of monocytes. The results are typically available within a few days.

What Do the Results Mean?

Results are usually reported as a count of monocytes per microliter of blood. While reference ranges can vary by lab, higher or lower than expected counts may signal potential health issues that need further evaluation by your healthcare provider.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated monocyte counts may indicate chronic infections, inflammation, or certain cancers. Lower than normal counts could suggest immune deficiencies, autoimmune disorders, or other blood-related conditions. Always discuss your results with your doctor, as they’ll consider your overall health and symptoms to interpret the findings accurately.

Short name

Monocyte count

Frequently asked questions

How often should I get this test?
Your doctor will determine how often you need this test based on your medical history, symptoms, and treatment plan. It may be part of routine check-ups, ongoing monitoring for a condition, or after an infection or injury.
What are common causes of abnormal monocyte counts?
Common causes of elevated monocytes include chronic infections (like tuberculosis), inflammatory diseases (such as rheumatoid arthritis), or certain cancers (like lymphoma). Low monocyte counts may occur due to immune system disorders, chemotherapy, or severe infections.
Can lifestyle changes affect monocyte counts?
Yes, lifestyle factors like diet, exercise, and stress can influence immune cell activity. Maintaining a balanced diet, staying hydrated, and managing stress may support overall immune health, but this test is primarily used for medical evaluation rather than general wellness monitoring.
  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