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Mononuclear Cell Count (Serum/Plasma)

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

This test measures the number of mononuclear white blood cells, which include lymphocytes and monocytes, in a blood sample.

Quick summary

["Understanding your mononuclear cell count can help assess immune function and inflammation."]

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

Key facts at a glance

LOINC
14382-6
Short code
Mononuc Cells NFr Snv Manual
Synonyms
Mononuc Cells NFr Snv 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

What Is a Mononuclear Cell?

Mononuclear cells are a type of white blood cell that play a key role in the immune system. They include lymphocytes (like B cells and T cells) and monocytes, which help fight infections and regulate immune responses. This test focuses on counting these cells rather than identifying specific types.

Why Might This Test Be Ordered?

Doctors may order this test to evaluate immune health, monitor conditions like chronic inflammation, or assess responses to treatments affecting white blood cells. It can also help diagnose or monitor certain blood disorders.

Sample Collection and Preparation

Blood is drawn from a vein, typically in the arm. The sample is processed to separate mononuclear cells from other blood components. The test may be performed on serum (liquid part of blood after clotting) or plasma (liquid part of blood without clotting).

What Does the Test Measure?

The test quantifies the total number of mononuclear cells present in the blood sample. While specific reference ranges vary by lab, this count helps identify deviations that may signal immune dysfunction or other health concerns.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Mononuclear Cells

Frequently asked questions

What Does a High or Low Count Mean?
A high mononuclear cell count may signal ongoing immune activity, such as in chronic infections or inflammatory diseases. A low count could suggest weakened immunity or conditions like leukemia or severe immune deficiency.
How Often Should I Get This Test?
The frequency depends on your health status and any ongoing medical conditions. Your healthcare provider will determine how often to check this test based on your treatment plan and symptoms.
Can Diet or Lifestyle Affect This Test?
While diet and lifestyle factors like stress or infections can influence white blood cell counts, this test specifically focuses on mononuclear cells. Your provider may recommend lifestyle adjustments if needed, but they will interpret results in the context of your overall health.
  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