Lymphocyte count (absolute cell count)
This test measures the number of lymphocytes, a type of white blood cell that helps fight infections and supports immune function.
["Your immune system’s key defender cells are checked here."]
Key facts at a glance
- LOINC
- 73904-5
- Short code
- CD3CD57
- Synonyms
- CD3-CD57+ Cells/lymph NFr Bld FC
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA) vacuum blood collection tube; sodium heparin (green-top) tube is also acceptable for flow cytometry
- Units
- N/A
- Ref low
- 2
- Ref high
- 15
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- flow-cytometry
- CPT
- 86356
- SNOMED
- 116646007
- Specimen volume
- 2-5 mL of whole blood (minimum 1 mL for pediatric samples)
- Stability
- Ambient temperature: 24-48 hours; refrigerated (2-8°C): up to 48 hours. Specimen should be processed within 24 hours of collection for optimal lymphocyte viability and marker expression. Do not freeze.
- Hemolysis max
- 100
- Lipemia max
- 200
- Icterus max
- 50
- TAT
- 4–48 hours
- Order
- routine
What Are Lymphocytes?
Lymphocytes are part of your immune system and include types like B cells, T cells, and natural killer cells. They help your body recognize and fight viruses, bacteria, and other invaders. This test focuses on the total count of lymphocytes in your blood.
Why Might This Test Be Done?
Doctors may order a lymphocyte count to evaluate immune function, diagnose conditions like infections, cancers (e.g., lymphoma), or autoimmune diseases, or monitor treatment responses.
How Is the Test Performed?
A small blood sample is drawn from your arm. The blood is then analyzed in a lab to count the lymphocytes. No special preparation is needed, but fasting may be advised if other blood tests are combined.
What Do Results Mean?
Results are typically reported as a number of lymphocytes per microliter (cells/µL) of blood. Lower than expected counts may suggest immune suppression, infections, or certain cancers. Higher counts could indicate chronic infections, inflammation, or overactive immune responses.
Reference range
CD3-CD57+ lymphocytes (NK cells): 2-15% of total lymphocytes; absolute count varies with total lymphocyte count. Reference ranges should be established by each laboratory based on local population data.N/A
No special patient preparation required. Recent corticosteroid therapy, chemotherapy, immunosuppressants, or acute illness may affect results and should be noted on the requisition.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Lymphocyte count
Frequently asked questions
Why do doctors check lymphocyte levels?
How often should I expect this test?
What can affect my lymphocyte count?
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.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 15, 2026. · Read our editorial policy