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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, in your blood. Lymphocytes help fight infections and are part of your immune system.

Quick summary

["Lymphocytes help protect your body from infections and diseases."]

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

Key facts at a glance

LOINC
9441-7
Short code
Lymphs IgD/lymph NFr WBC
Synonyms
Lymphs IgD/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?

Doctors may order a lymphocyte count to diagnose or monitor conditions like infections, immune disorders (such as lupus or HIV), blood cancers (like leukemia), or to check for immune system responses after treatments like chemotherapy or organ transplants. It can also help evaluate conditions affecting the bone marrow or lymph nodes.

What Does the Test Involve?

A small sample of your blood is taken from a vein, usually in your arm. The blood is then analyzed in a lab to count the lymphocytes. This is a quick and painless procedure.

What Are Normal Results?

Normal results vary and depend on your age, overall health, and other factors. There are no specific reference ranges provided here since they can differ by lab and individual health status.

What Are Possible Results?

Results can show high (elevated) or low (reduced) lymphocyte counts. Elevated counts might indicate an overactive immune response, while low counts could suggest immune suppression, infection, or other health issues.

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.

Clinical Significance

Short name

Lymphocyte Count

Frequently asked questions

What Might Cause Abnormal Results?
High lymphocyte counts can be seen in chronic infections, certain cancers (like lymphoma), or autoimmune diseases. Low lymphocyte counts may occur with infections, immune deficiencies, or treatments that weaken the immune system, such as chemotherapy.
How Do I Prepare for This Test?
No special preparation is usually needed. However, avoid heavy exercise or eating a large meal before the test if instructed by your healthcare provider.
What Are Common Side Effects?
The most common side effect is a slight bruise or soreness at the needle insertion site. Rarely, there may be mild pain or swelling. If you experience excessive bleeding or signs of infection at the site, contact your healthcare provider.
  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