Absolute count of CD3+ cells in peripheral blood
This test measures the number of CD3+ cells, a type of white blood cell that plays a key role in the immune system. CD3+ cells are part of T lymphocytes, which help fight infections and regulate immune responses.
["CD3+ cells help your immune system respond to infections and maintain immune balance."]
Key facts at a glance
- LOINC
- 106961-6
- Short code
- CD3CD5
- Synonyms
- CD3+CD5+ cells NFr Bld FC
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA (lavender/purple-top) anticoagulant tube; sodium heparin (green-top) tube is also acceptable for flow cytometry immunophenotyping
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- flow-cytometry
- CPT
- 86359
- SNOMED
- 426620008
- Specimen volume
- 3–5 mL of whole blood (adult); 1–2 mL (pediatric); minimum 0.5 mL acceptable for neonates
- Stability
- Specimen must be processed within 24–48 hours of collection when stored at room temperature (18–25 °C). Do not refrigerate or freeze. Prolonged storage >48 hours results in loss of cell viability and altered antigen expression.
- Hemolysis max
- 100
- Lipemia max
- 500
- Icterus max
- 40
- TAT
- 4–48 hours
- Order
- routine
Why Is This Test Done?
Doctors may order this test to evaluate immune function, assess for immune deficiencies, monitor immune-related conditions (such as certain cancers or autoimmune diseases), or check for infections. It can also help diagnose or monitor conditions like HIV, lymphoma, or other T-cell disorders.
What Does a Low or High Count Mean?
A lower-than-expected count of CD3+ cells might suggest immune system problems, such as severe T-cell deficiencies or certain cancers. A higher-than-expected count could indicate overactive immune responses or conditions like certain infections or inflammatory diseases.
Sample Collection and Preparation
This test requires a simple blood draw from a vein in your arm. The blood sample is processed to count the CD3+ cells, which are part of your white blood cell population. No special preparation is needed, but fasting may not be required unless instructed by your healthcare provider.
What to Expect During the Test
You may feel slight discomfort during the blood draw, but most people experience minimal pain. Afterward, you can resume normal activities. If you have a hard time sitting still, let your healthcare provider know to help ensure a smooth process.
Reference range
Reported as cells/μL and percentage of total lymphocytes. Adult reference ranges vary by laboratory; typical reference range is approximately 800–2,500 cells/μL or 60–85% of total lymphocytes for CD3+ T cells. CD5 is normally expressed on the majority of mature T cells; CD3+CD5+ subset comprises approximately 60–80% of lymphocytes. Pediatric ranges are higher in young children and gradually decline to adult values by adolescence.N/A
No fasting required. Patients should be well-hydrated. Avoid recent (within 24–48 hours) high-dose corticosteroid or immunosuppressive therapy if possible, as these may transiently alter lymphocyte subset counts; document any recent immunomodulatory treatments. Avoid strenuous exercise immediately prior to collection.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance
Short name
CD3+ Lymphocyte Count
Frequently asked questions
What does a changed CD3+ cell count mean for my health?
How often should I get this test?
Can I eat or drink before 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