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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 your immune system fight infections and diseases.

Quick summary

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

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

Key facts at a glance

LOINC
67833-4
Short code
Lymphocytes # Plr Fetus
Synonyms
Lymphocytes # Plr Fetus
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
86430
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may order this test to check for signs of immune system issues, such as infections, inflammation, or conditions like leukemia, lymphoma, or HIV. It can also help monitor treatments for certain diseases or conditions that affect the immune system.

What to Expect Before the Test

You won’t need any special preparation. The test involves a simple blood draw from a vein, usually in your arm. It’s quick and typically painless, though you might feel a slight pinch or discomfort for a few seconds.

What the Test Results Mean

Lymphocyte counts can vary based on your overall health, age, and activity level. High counts might suggest an active infection, immune response, or certain blood disorders. Low counts could indicate immune suppression, chronic illnesses, or treatments that affect white blood cells.

Common Conditions Affecting Lymphocyte Counts

Changes in lymphocyte levels can signal conditions like autoimmune diseases (e.g., lupus), infections (e.g., COVID-19, HIV), or cancers (e.g., non-Hodgkin lymphoma). Your provider will interpret results in the context of your medical history and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Lymphocyte Count

Frequently asked questions

Will my results affect my treatment plan?
Yes, your results will be reviewed by your healthcare provider to guide decisions about treatments, such as medications, lifestyle changes, or further testing. They’ll consider your overall health and any symptoms you’re experiencing.
How long will I need to wait for results?
Results are typically available within a few days to a week, depending on your lab’s processing time. Your provider will contact you once they’re ready to discuss them.
Can lifestyle changes impact my lymphocyte count?
Yes, factors like diet, stress, sleep, and exercise can influence white blood cell counts. Avoiding infections, managing stress, and maintaining good hygiene may help support your immune system, but this test is primarily for diagnostic purposes.
  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