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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 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
68407-6
Short code
Lymphocytes # Vitf Manual
Synonyms
Lymphocytes # Vitf Manual
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
manual-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 This Test Might Be Ordered

Your healthcare provider may order this test to check for immune system issues, monitor conditions like infections, cancers, or autoimmune diseases, or evaluate symptoms such as frequent illnesses, fatigue, or unexplained weight loss.

What to Expect Before the Test

No special preparation is needed. You may have a simple blood draw from a vein in your arm, similar to other routine blood tests. You might feel a slight pinch or discomfort, but it usually lasts only a moment.

What the Results Mean

Results are typically reported as a count of lymphocytes per microliter (µL) of blood. While reference ranges can vary slightly by lab, lower than expected counts may indicate immune suppression, while higher counts could suggest infection, inflammation, or certain diseases.

Common Conditions Affecting Results

Low lymphocyte counts might be linked to conditions like HIV/AIDS, chemotherapy, or certain autoimmune diseases. High counts could be seen in chronic infections, certain cancers, or overactive immune responses.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lymphocyte Count

Frequently asked questions

What causes my lymphocyte count to change?
Several factors can affect lymphocyte counts, including infections (like colds or flu), chronic illnesses, immune system disorders, medications (such as steroids or chemotherapy), or even stress and diet. If you notice changes, discuss them with your doctor.
How often should I get this test?
The frequency depends on your health condition and treatment plan. Your healthcare provider will determine how often to check your lymphocyte count, whether it’s part of routine care or monitoring a specific condition.
Can lifestyle changes impact my lymphocyte count?
Yes, lifestyle factors like diet, sleep, exercise, and managing stress can influence your immune system. Eating a balanced diet, staying hydrated, and reducing stress may support healthier lymphocyte levels, but always follow your doctor’s advice.
  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