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Lymphocyte Count in Whole Blood

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

This test measures the number of lymphocytes, a type of white blood cell important for fighting infections and maintaining immune function.

Quick summary

["Lymphocytes help protect your body from illness and infection."]

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

Key facts at a glance

LOINC
17222-1
Short code
Lymphs HLE/lymph NFr Bld
Synonyms
Lymphs HLE/lymph 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 Lymphocyte Count Used For?

A lymphocyte count helps doctors assess your immune system’s strength. It can be useful in diagnosing conditions like infections, autoimmune diseases, or certain cancers. Low levels may indicate immune deficiencies, while high levels could suggest overactive immune responses or certain infections.

When Might You Need This Test?

You may need a lymphocyte count if you have symptoms like frequent infections, unexplained fatigue, or if your doctor suspects an immune-related condition. It’s also part of routine blood tests for people with weakened immune systems or those undergoing treatments like chemotherapy.

How Is the Test Performed?

A small amount of your blood is drawn from a vein, usually in your arm. The sample is then analyzed in a lab to count the lymphocytes. This test is quick and typically done as part of a full blood count (CBC).

What Are Common Results and Their Meanings?

Results are usually reported as a count of lymphocytes per microliter (µL) of blood. While specific reference ranges vary by lab, lower-than-normal counts may signal immune issues, while higher-than-normal counts may indicate inflammation, infection, or other conditions. Your doctor will interpret results in the context of your overall health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Why Does This Test Matter?

Short name

Lymphocyte Count

Frequently asked questions

Why was I asked to get this test?
Your doctor may recommend this test to check if your immune system is functioning properly, especially if you’ve had frequent infections, unexplained weight loss, or symptoms like fatigue. It can also help monitor conditions like HIV, lymphoma, or other immune disorders.
What does a low or high lymphocyte count mean?
A low lymphocyte count might suggest an immune deficiency, such as HIV/AIDS, certain cancers, or long-term illness. A high count could indicate an overactive immune response, chronic infections, or conditions like leukemia. Always discuss your results with your healthcare provider.
How often should I get this test?
The frequency depends on your health and medical needs. If you have a chronic condition, your doctor may order this test regularly. If it’s part of routine blood work, it may be done less often, such as every few months or annually.
  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