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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 maintain immune function.

Quick summary

["Lymphocyte count helps assess your immune system’s health and response to infections or treatments."]

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

Key facts at a glance

LOINC
27936-4
Short code
Lymphocytes NFr Spt
Synonyms
Lymphocytes NFr Spt
Category
chemistry
Sample
sputum
Container
Sterile sputum container
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
85610
SNOMED
396252006
Specimen volume
3-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
TAT
4–24 hours
Order
routine

Why This Test Is Done

Doctors may order a lymphocyte count to diagnose or monitor conditions like infections, immune disorders (such as lupus or rheumatoid arthritis), certain cancers (like lymphoma or leukemia), or to evaluate how your body responds to treatments like chemotherapy or steroids.

What to Expect During the Test

This test is typically done by taking a small blood sample from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause significant discomfort. The sample is then analyzed in a lab to count your lymphocytes.

Possible Results and Interpretation

Results are usually reported as a count of lymphocytes per microliter (µL) of blood. While specific reference ranges vary by lab, lower than expected counts may suggest immune suppression, while higher counts could indicate overactive immune responses or certain infections.

Common Conditions Affecting Lymphocyte Count

Low lymphocyte counts can be linked to conditions like HIV/AIDS, certain cancers, or treatments that weaken the immune system. High counts may be seen in chronic infections, autoimmune diseases, or after vaccination.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: sputum

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lymphocyte Count

Frequently asked questions

What does a low lymphocyte count mean?
A low lymphocyte count may indicate weakened immune function, which can be caused by infections, certain medications, or underlying health conditions like HIV or autoimmune diseases. Your doctor will discuss next steps based on your overall health and symptoms.
How often should I get this test?
The frequency depends on your medical condition. If you have an ongoing health issue (like cancer or an immune disorder), your doctor may recommend regular testing. If you’re healthy, this test is usually not routine unless symptoms suggest a need for evaluation.
Can lifestyle changes affect lymphocyte counts?
Yes, lifestyle factors like diet, stress, and sleep can influence immune function. Maintaining a balanced diet, staying hydrated, and managing stress may support healthy white blood cell counts, but this test alone doesn’t replace medical advice for underlying conditions.
  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