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Lymphocyte Count (Qualitative Peripheral Blood Manual Examination)

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

This test evaluates the presence and relative proportions of lymphocytes, a type of white blood cell, in your blood. It helps assess immune function and identify potential infections, immune disorders, or other blood-related conditions.

Quick summary

["Lymphocytes play a key role in fighting infections and maintaining immune health."]

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

Key facts at a glance

LOINC
14820-5
Short code
Lymphocytes NFr Plr Manual
Synonyms
Lymphocytes NFr Plr Manual
Category
chemistry
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
manual-count
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 Test Used For?

A lymphocyte count test is often used to diagnose or monitor conditions such as infections (e.g., viral or bacterial), immune deficiencies, or diseases like lymphoma or leukemia. It may also be part of routine blood work to check overall immune health.

How Is This Test Performed?

This test involves drawing a small sample of blood from a vein in your arm. The sample is then examined under a microscope by a trained technician to count and assess the types of white blood cells, including lymphocytes, manually.

What Does the Test Result Mean?

Results are qualitative (descriptive rather than numerical), indicating whether lymphocyte levels appear normal, elevated, or reduced compared to standard expectations. Abnormal findings may prompt further testing or evaluation by your healthcare provider.

Common Conditions That May Require This Test

Your doctor may recommend this test if you have symptoms like frequent infections, unexplained fatigue, swollen lymph nodes, or if you’re undergoing treatment for conditions that affect the immune system.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lymphocyte Screen

Frequently asked questions

Why might my doctor order this test?
Your doctor may order this test to check for immune-related issues, monitor treatment effectiveness, or investigate unexplained symptoms like frequent infections or fatigue.
What are the typical preparation steps for this test?
No special preparation is needed. You can eat, drink, and go about your normal activities as usual. Avoid heavy exercise or stress before the test if advised by your provider.
Will the test results affect my daily routine?
Results are typically reviewed by your healthcare provider and won’t directly impact your daily activities unless further testing or treatment is recommended.
  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