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Lymphocyte count (peripheral blood, automated cell differential)

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 illness and infection."]

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

Key facts at a glance

LOINC
20619-3
Short code
Lymphocytes NFr Spec Auto
Synonyms
Lymphocytes NFr Spec Auto
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
automated-count
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 Might This Test Be Done?

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

What to Expect Before the Test

No special preparation is needed for this test. You’ll have a small needle inserted into your arm to draw blood, similar to a routine blood draw. The process usually takes a few minutes.

What the Test Results Mean

Lymphocyte counts can vary depending on your overall health, age, and medical conditions. Abnormally high or low counts may signal underlying health concerns that need further evaluation by a healthcare provider.

Common Conditions Monitored

High lymphocyte counts might indicate chronic infections, certain cancers (like lymphoma), or immune disorders. Low counts could suggest infections, autoimmune diseases, or treatments that suppress the immune system.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical significance: Abnormal lymphocyte counts can signal immune system dysfunction, infection, or cancer. Your provider will interpret results in the context of your medical history and symptoms.

Short name

Lymphocyte count

Frequently asked questions

What causes a lymphocyte count to change?
Several factors can affect lymphocyte levels, including infections (like colds or flu), chronic illnesses, medications (such as chemotherapy), or autoimmune conditions. Stress, diet, and even sleep can also influence blood cell counts.
How long does it take to get results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing schedule. Your healthcare provider will discuss the findings with you during your follow-up visit.
Can lifestyle changes impact lymphocyte counts?
Yes, lifestyle factors like diet, exercise, sleep, and stress can influence immune cell activity. Maintaining a balanced diet, staying hydrated, and managing stress may support overall immune health, though this test alone won’t show direct lifestyle effects.
  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