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Lymphocyte Count (Peripheral Blood)

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

This test measures the number of lymphocytes, a type of white blood cell, in your blood. Lymphocytes help fight infections and are part of your immune system.

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
56774-3
Short code
Lymphocytes NFr Tiss
Synonyms
Lymphocytes NFr Tiss
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What Is a Lymphocyte Count Used For?

Doctors may order a lymphocyte count to evaluate your immune system, diagnose conditions like infections, autoimmune diseases, or certain cancers, or monitor treatment progress. It can also help identify if your immune response is too strong or too weak.

How Is This Test Performed?

A small blood sample is drawn from a vein, usually in your arm. The blood is then analyzed in a lab to count the lymphocytes among other white blood cells.

What Does a Lymphocyte Count Tell You?

A high lymphocyte count may suggest an active infection, chronic inflammation, or certain immune disorders. A low lymphocyte count could indicate immune suppression, certain cancers, or side effects from treatments like chemotherapy.

Common Conditions Monitored

This test is often used to monitor conditions such as leukemia, lymphoma, HIV/AIDS, or other immune-related diseases. It can also help assess how well your body is responding to treatments like chemotherapy or steroids.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lymphocyte Count

Frequently asked questions

Why might my doctor order a lymphocyte count test?
Your doctor may order this test if you have symptoms like frequent infections, unexplained weight loss, fatigue, or if you’re undergoing treatment for a condition that affects your immune system.
What are typical reference ranges for lymphocyte counts?
Reference ranges can vary by lab and age. Generally, healthy adults typically have between 1,500 and 4,500 lymphocytes per microliter of blood, but these numbers can differ based on individual health and medical conditions.
Can lifestyle factors, like diet or stress, affect lymphocyte counts?
Yes, lifestyle factors such as poor nutrition, chronic stress, or certain medications can influence lymphocyte levels. It’s important to discuss any changes in your health or lifestyle with your doctor.
  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