Skip to content

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 your immune system fight infections and diseases.

Quick summary

["Lymphocytes are key to your body’s defense system."]

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

Key facts at a glance

LOINC
30118-4
Short code
Lymphs IgA # WBC
Synonyms
Lymphs IgA # 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

What Is a Lymphocyte Count?

Lymphocytes are part of your immune system and include different types such as B cells, T cells, and natural killer cells. Your doctor may order this test to check for infections, immune disorders, or other health conditions that affect your white blood cell count.

Why Might Your Doctor Order This Test?

A doctor might order a lymphocyte count to evaluate symptoms like frequent infections, unusual fatigue, swelling, or unexplained weight changes. It can also be used during cancer treatment to monitor immune function or before certain vaccines to ensure your immune system is strong.

How Is This Test Done?

This test involves drawing a small amount of blood from a vein in your arm. The blood is then analyzed in a lab to count the number of lymphocytes. The results help determine if your immune system is functioning normally or if there may be an issue.

What Do the Results Mean?

Results may show a higher or lower-than-normal count of lymphocytes, which can indicate different health conditions. For example, a low lymphocyte count might suggest an immune disorder, while a high count could be linked to infections or certain cancers.

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

How Often Will I Need This Test?
The frequency of this test depends on your health condition and treatment plan. Your doctor will let you know how often you need follow-up tests based on your specific situation.
What Are the Possible Side Effects of Blood Drawing?
Most people experience mild discomfort or bruising at the injection site. Rarely, there may be a slight swelling or redness, but these usually go away quickly. If you experience severe pain, excessive bleeding, or signs of infection (like fever or increased redness), contact your doctor.
Can I Eat or Drink Before This Test?
You can usually eat and drink normally before this test unless your doctor gives specific instructions. Blood tests are generally done on an empty stomach for some tests, but lymphocyte counts do not require fasting.
  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