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Lymphocyte Count (Serum or Plasma)

Published: August 9, 2026Updated: August 16, 2026

This test measures the number of lymphocytes in your blood, a type of white blood cell that helps fight infections and supports immune function.

Quick summary

["Lymphocytes help protect your body against illness and infection."]

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

Key facts at a glance

LOINC
35049-6
Short code
Lymphocytes # Snv
Synonyms
Lymphocytes # Snv
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

What Is a Lymphocyte Count Used For?

A lymphocyte count helps doctors assess your immune system health. It may be used to diagnose or monitor conditions like infections, autoimmune diseases, or certain cancers. Low or high counts can signal underlying health issues that need further evaluation.

When Might You Need This Test?

Your doctor might order a lymphocyte count if you have symptoms like frequent infections, unexplained fatigue, or if you’re undergoing treatment for conditions like cancer, HIV, or autoimmune disorders. It can also be part of routine blood work for general health checks.

How Is the Test Performed?

A small blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab, where it’s analyzed to count the number of lymphocytes. Results are typically available within a few days.

What Do the Results Mean?

Results are compared to standard ranges for healthy adults, but individual ranges can vary. Low lymphocyte counts may indicate immune suppression, while high counts could suggest infection, inflammation, or other conditions. Your doctor will interpret results in the context of your overall health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lymphocyte Level

Frequently asked questions

Why might my lymphocyte count be different from what’s listed as normal?
Normal ranges can vary based on age, health status, and lab methods. Factors like recent illness, medications, or stress can also temporarily affect your count. Your doctor will consider these factors when reviewing your results.
Can lifestyle changes, like diet or exercise, affect my lymphocyte count?
Yes, certain foods, hydration, and even sleep can influence immune cell activity. While diet alone won’t change your test results, maintaining overall health supports better immune function.
Do I need to prepare for this test?
No special preparation is needed, but avoid heavy meals before the blood draw. If you’re on certain medications or have a history of bleeding disorders, let your doctor know before the test.
  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