Skip to content

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 your immune system fight infections and diseases.

Quick summary

["Knowing your lymphocyte count can help identify immune function or potential health concerns."]

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

Key facts at a glance

LOINC
26480-4
Short code
Lymphocytes NFr Pcar
Synonyms
Lymphocytes NFr Pcar
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Is Done

Doctors may order a lymphocyte count to diagnose or monitor conditions like infections, autoimmune diseases, or cancers. It can also help assess immune response after treatments like chemotherapy or organ transplants.

What to Expect Before the Test

No special preparation is needed. You may have a simple blood draw, usually done in a doctor’s office or lab. The process is quick and typically painless.

What the Results Mean

Results show the absolute number of lymphocytes in your blood. While reference ranges vary by lab, low counts may suggest immune suppression, while high counts could indicate infection, inflammation, or certain diseases.

Common Conditions Affecting Results

Lymphocyte counts can be affected by infections (like COVID-19 or HIV), chronic illnesses (such as lupus or rheumatoid arthritis), or treatments like steroids or chemotherapy.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Low lymphocyte counts may signal weakened immunity, prompting further testing or adjustments to treatment. High counts could indicate overactive immune responses or hidden infections. Your doctor will interpret results in the context of your overall health and symptoms.

Short name

Lymphocyte Count

Frequently asked questions

What causes low lymphocyte counts?
Low lymphocyte counts can result from infections, autoimmune diseases, certain medications (like steroids), or conditions that drain immune cells, such as HIV/AIDS or chemotherapy.
High lymphocyte counts may occur with infections (e.g., viral or bacterial), chronic inflammatory diseases, or conditions like lymphoma or leukemia. Stress or certain medications can also temporarily raise counts.
Yes—diet, sleep, and stress management can influence immune function. Avoiding smoking, eating nutrient-rich foods, and reducing stress may support healthier lymphocyte levels, though results depend on overall health.
When should I ask my doctor about lymphocyte test results?
Ask your doctor if you have symptoms like frequent infections, unexplained fatigue, or if your test results fall outside typical ranges for your health. They’ll help determine if further action is needed.
  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