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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 that helps protect your body from infections and diseases.

Quick summary

["Lymphocytes help fight infections and support immune function."]

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

Key facts at a glance

LOINC
9442-5
Short code
Lymphs IgG/lymph NFr WBC
Synonyms
Lymphs IgG/lymph NFr WBC
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
4.5
Ref high
11
Critical range
2 N/A – 30 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85004
SNOMED
900000000000003002
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

Why Is This Test Done?

Your doctor may order a lymphocyte count to check for immune system issues, monitor conditions like infections, cancers (such as lymphoma), or autoimmune diseases, or evaluate responses to treatments. It can also be part of a general blood test to assess overall health.

What Does a Lymphocyte Count Tell You?

A lymphocyte count can indicate whether your immune system is functioning normally. Low counts might suggest immune deficiencies or certain infections, while high counts could point to chronic infections, certain cancers, or overactive immune responses.

How Is This Test Performed?

A small amount of blood is drawn from a vein, usually in your arm, and sent to a lab. The lab analyzes the blood sample to count the lymphocytes among other white blood cells.

What Are Common Results and Their Meanings?

While specific reference ranges can vary by lab, results are often interpreted in relation to your overall health and medical history. Your doctor will discuss any findings with you.

Reference range

Adult: 4.5-11.0 x 10^9/LN/A

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lymphocyte Count

Frequently asked questions

What Does a Low Lymphocyte Count Mean?
A low lymphocyte count may indicate an immune system that isn’t working as well as it should. This could be due to certain medications, infections, genetic conditions, or diseases like HIV/AIDS. Your doctor will determine the cause and recommend next steps, such as adjusting treatments or additional tests.
What Does a High Lymphocyte Count Mean?
High lymphocyte counts can occur with chronic infections, certain cancers (like leukemia or lymphoma), or autoimmune diseases. It may also be seen in response to stress or inflammation. Your doctor will review your symptoms and medical history to understand the reason and guide further care.
How Often Should I Get This Test?
The frequency depends on your health status and any conditions you have. Your doctor will let you know if this test is needed regularly, occasionally, or only under specific circumstances, such as before starting certain treatments.
  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