Absolute Lymphocyte Count (from Whole Blood)
This test measures the number of lymphocytes (a type of white blood cell) in your blood, which helps assess your immune system’s strength.
["Lymphocytes are key defenders against infections and help your body recognize and fight foreign invaders."]
Key facts at a glance
- LOINC
- 89354-5
- Short code
- CD19CD21
- Synonyms
- CD19+21- cells # Bld
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA (purple-top) blood collection tube; sodium heparin (green-top) tube is acceptable for flow cytometry
- Units
- N/A
- Ref low
- 50
- Ref high
- 300
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Flow Cytometry with Fluorescent-Activated Cell Sorting (FACS); Immunophenotyping using CD19 and CD21 monoclonal antibodies
- CPT
- 86356
- SNOMED
- 122501000221101
- Specimen volume
- 3-5 mL of whole blood (pediatric: 1-2 mL minimum)
- Stability
- Specimen should be processed within 24-48 hours of collection when stored at room temperature (18-22°C). Do not refrigerate or freeze. Viability of lymphocytes decreases significantly beyond 48 hours.
- Hemolysis max
- 50
- Lipemia max
- 200
- Icterus max
- 20
- TAT
- 24–72 hours
- Order
- routine
Why This Test Might Be Ordered
Your doctor may recommend this test to evaluate your immune system, check for infections, monitor conditions like leukemia, or assess responses to treatments such as chemotherapy or immune-modulating therapies.
What to Expect Before the Test
No special preparation is needed. You’ll provide a small sample of whole blood, usually drawn from your arm. The process is quick and typically painless.
What the Results Mean
Results are compared to standard ranges for healthy adults. Low counts may indicate immune suppression, infections, or certain cancers, while high counts could signal chronic inflammation or other conditions.
Common Conditions Affecting Results
Changes in lymphocyte count can occur with infections (like COVID-19 or flu), autoimmune diseases (such as lupus or rheumatoid arthritis), or treatments that weaken the immune system.
Reference range
Reference ranges vary by laboratory and age. Adult values typically range from 50-300 cells/μL. Pediatric and geriatric populations may have different reference intervals. Please refer to the specific reference range provided by the performing laboratory.N/A
No special preparation required. Fasting is not necessary. Patients should be well-hydrated prior to venipuncture. Recent corticosteroid therapy, chemotherapy, or immunosuppressive medications may affect results and should be documented.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Lymphocyte counts are crucial for diagnosing and managing conditions like HIV/AIDS, certain cancers (e.g., lymphoma), and evaluating immune responses to vaccines or medications.
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 15, 2026. · Read our editorial policy