Lymphocyte count (absolute)
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 from illness and infection."]
Key facts at a glance
- LOINC
- 97598-7
- Short code
- NKCELLS-LR
- Synonyms
- CD3-CD16+CD56+ Cells/lymph NFr L resp FC
- Category
- chemistry
- Sample
- serum
- Container
- Sterile, leak-proof container for lower respiratory specimen (bronchoalveolar lavage fluid, bronchial washings, or tracheal aspirate); collection in saline as appropriate
- Units
- N/A
- Ref low
- 5
- Ref high
- 20
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- flow-cytometry
- CPT
- 86356
- SNOMED
- 122565008
- Specimen volume
- Minimum 2 mL of lower respiratory specimen; larger volumes (10-50 mL BAL) preferred for adequate cell yield
- Stability
- Process within 4 hours of collection at room temperature (15-25°C); do not refrigerate or freeze as this compromises cell viability and surface marker integrity
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
What Are Lymphocytes?
Lymphocytes are a key part of your immune system. They include B cells, T cells, and natural killer cells, each playing a role in identifying and destroying harmful substances like bacteria, viruses, and abnormal cells. Your body produces lymphocytes in your bone marrow and lymph nodes. When you get sick, your lymphocyte count may rise to help fight the infection.
Why Might You Need This Test?
Doctors may order a lymphocyte count test to diagnose or monitor conditions affecting your immune system, such as infections, certain cancers (like lymphoma or leukemia), autoimmune diseases, or to check how well your immune response is working after treatments like chemotherapy.
How Is This Test Done?
A small sample of your blood is taken from a vein, usually in your arm. The blood is then sent to a lab, where it is analyzed to count the number of lymphocytes. This test is quick and painless, and you can return to your normal activities right after.
What Do the Results Mean?
Results show the total number of lymphocytes in your blood. While specific reference ranges can vary by lab, low or high counts may signal underlying health issues that need further evaluation by your healthcare provider.
Reference range
Reference ranges vary by laboratory; generally expressed as a percentage of total lymphocytes and as absolute count per microliter. NK cells typically constitute 5-20% of peripheral blood lymphocytes (approximately 90-600 cells/μL in adults)N/A
No special patient preparation required. Inform the laboratory of any recent immunosuppressive therapy, chemotherapy, or biologic agent use as these may affect NK cell counts
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Lymphocyte count
Frequently asked questions
What causes a low lymphocyte count?
What causes a high lymphocyte count?
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