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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 maintain immune function.

Quick summary

Your lymphocyte count helps assess your immune health and response to infections or treatments.

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

Key facts at a glance

LOINC
95831-4
Short code
Lymphocyte dose in HPC trsplt Patient
Synonyms
Lymphocyte dose in HPC trsplt Patient
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

Why This Test Is Done

Doctors may order a lymphocyte count to diagnose or monitor conditions like infections (e.g., viral, bacterial), immune disorders (e.g., HIV, lymphoma), or autoimmune diseases. It can also help evaluate how well your immune system is responding to treatments, such as chemotherapy or certain medications.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a blood sample. The process usually takes a few minutes. If you’re nervous, let your healthcare provider know—they can help make it more comfortable.

What the Results Mean

Lymphocyte counts can vary based on your overall health, age, and medical conditions. A lower than normal count may indicate immune suppression, while a higher count could suggest infection, inflammation, or certain diseases. Your doctor will interpret the results in the context of your medical history and other tests.

Common Conditions Affecting Results

Changes in lymphocyte counts can occur with infections (e.g., COVID-19, mononucleosis), chronic illnesses (e.g., diabetes, kidney disease), or treatments that weaken the immune system (e.g., steroids, chemotherapy). Some genetic or autoimmune conditions may also alter lymphocyte levels.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Lymphocyte counts are critical for diagnosing and managing immune-related disorders. Low counts may signal an inability to fight infections, while elevated counts could point to overactive immune responses or underlying diseases. Regular monitoring helps track immune health and treatment effectiveness.

Short name

Lymphocyte Count

Frequently asked questions

What causes a low lymphocyte count?
Low lymphocyte counts can result from infections (like HIV or severe viral illnesses), certain medications (e.g., chemotherapy, steroids), autoimmune diseases, or conditions that drain immune cells (e.g., malnutrition, liver disease). Chronic stress or sleep deprivation may also temporarily lower counts.
How long does it take to get results from this test?
Results from a lymphocyte count are typically available within 1 to 3 business days, depending on your lab’s processing time. Your healthcare provider will contact you once they have the results, usually within a few days of receiving them from the lab.
Can lifestyle changes affect lymphocyte counts?
Yes, lifestyle factors like diet (e.g., balanced nutrition, vitamin deficiencies), sleep (e.g., poor sleep can lower immune function), and stress management can influence lymphocyte levels. Maintaining a healthy lifestyle may help support normal immune function, but this test alone won’t diagnose underlying issues without medical evaluation.
  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