Lymphocyte Count (Blood)
This test measures the number of lymphocytes, a type of white blood cell that helps your immune system fight infections and diseases.
["Lymphocytes help protect your body by identifying and attacking harmful invaders like bacteria and viruses."]
Key facts at a glance
- LOINC
- 107064-8
- Short code
- CD3T
- Synonyms
- Cells.CD3+CD19- (T cells)/lymph NFr Bld FC
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA) tube or specialized flow cytometry blood collection tube (e.g., BD Vacutainer CPT or ACD-A tube) per laboratory protocol
- Units
- N/A
- Ref low
- 58
- Ref high
- 84
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- flow-cytometry
- CPT
- 86359
- SNOMED
- 395130001
- Specimen volume
- 3–5 mL of whole blood for adults; 1–3 mL for pediatric patients; minimum 1 mL
- Stability
- Specimen should be processed within 24–48 hours of collection when stored at room temperature (18–25°C). Refrigeration (2–8°C) may extend viability to 48 hours for some markers but can affect certain surface antigens; refer to laboratory-specific stability guidelines.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What Are Lymphocytes?
Lymphocytes are a subset of white blood cells that play a crucial role in your immune response. They include B cells, T cells, and natural killer cells, each with specialized functions in defending your body against infections and preventing diseases like cancer.
Why Might You Need This Test?
Doctors may order a lymphocyte count to diagnose or monitor conditions such as infections, immune disorders (like lupus or rheumatoid arthritis), certain cancers (like leukemia), or to check how your immune system is responding to treatment.
How Is the Test Done?
A small amount of blood is drawn from a vein, usually in your arm. The sample is then analyzed in a lab to count the number of lymphocytes present in your blood.
What Do Results Mean?
Results are typically reported as a count per microliter (µL) of blood. Lower-than-normal counts may suggest immune deficiencies or infections, while higher-than-normal counts could indicate chronic inflammation, certain cancers, or autoimmune diseases.
Reference range
Adults: CD3+ T cells typically 58–84% of total lymphocytes (absolute count varies with total lymphocyte count). Pediatric reference ranges differ by age; consult age-specific reference table provided by the performing laboratory.N/A
No fasting required. Patients should avoid recent corticosteroid or immunosuppressive therapy if possible, as these can transiently alter lymphocyte subset distributions. Inform the laboratory of any recent blood transfusions or immunomodulatory medications.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
Lymphocyte Count
Frequently asked questions
Why do I need this test?
What if my lymphocyte count is low?
How often should I get this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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