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Lymphocyte Count (Manual Differential Count)

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

This test measures the number of lymphocytes, a type of white blood cell, in your blood. It helps assess immune function and identify potential infections or immune disorders.

Quick summary

["Lymphocytes help fight infections and regulate your immune system."]

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

Key facts at a glance

LOINC
11108-8
Short code
Lymphocytes NFr Mar Manual
Synonyms
Lymphocytes NFr Mar 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 Is This Test Done?

Your healthcare provider may order this test to evaluate your immune system, diagnose conditions like infections, autoimmune diseases, or blood disorders, or monitor treatment responses. It’s often part of a complete blood count (CBC) but can be done manually for detailed differential analysis.

What Does the Test Involve?

A small blood sample is drawn from a vein, typically in your arm. The sample is then examined under a microscope by a trained technician to count and classify different types of white blood cells, including lymphocytes.

How Is the Result Interpreted?

Results are expressed as the absolute count of lymphocytes per microliter (µL) of blood. While reference ranges vary by lab, lower than expected counts may suggest immune suppression, while higher counts could indicate infection, inflammation, or other conditions.

What Are Common Causes of Abnormal Results?

Low lymphocyte counts may occur due to infections (like HIV), certain medications, or immune system disorders. High counts can result from chronic infections, certain cancers, or stress-related immune responses.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: This test is critical for diagnosing and managing conditions affecting the immune system. For example, it can help identify lymphocytic leukemia, chronic infections, or autoimmune diseases like lupus, where lymphocyte levels may be elevated or suppressed.

Short name

Manual Lymphocyte Count

Frequently asked questions

What if I Have Questions About My Results?
If your lymphocyte count is outside the expected range, discuss your results with your healthcare provider. They can explain what the numbers mean in your specific situation and recommend next steps, such as additional tests or treatments.
Will This Test Affect My Medications?
Some medications, like chemotherapy or immunosuppressants, can temporarily lower lymphocyte counts. Always inform your doctor about all medications you’re taking to avoid interactions or unexpected test results.
How Often Should I Get This Test?
Frequency depends on your health condition. Your provider may recommend this test periodically if you have an ongoing immune-related illness, are undergoing treatment, or are at higher risk for infections.
  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