Activtlymphsnfrspec
This blood test measures the number of activated T cells (a type of white blood cell) in your blood to help evaluate your immune system function.
{"Measures activated T lymphocytes in blood","Helps diagnose immune system disorders","Requires a blood sample (serum)","Results show percentage or absolute count of activated T cells","Used to monitor conditions like HIV, autoimmune diseases, and immune deficiencies"}
Key facts at a glance
- LOINC
- 20632-6
- Short code
- ACT-T
- Synonyms
- Activ T Lymphs NFr Spec
- Category
- chemistry
- Sample
- serum
- Container
- EDTA (purple top) tube for whole blood collection
- Units
- N/A
- Ref low
- 10
- Ref high
- 30
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Flow cytometry immunophenotyping with monoclonal antibody staining
- CPT
- 86356
- SNOMED
- 781001
- Specimen volume
- 3-5 mL of whole blood in EDTA tube
- Stability
- Room temperature: 24-48 hours. Refrigerated (2-8°C): up to 72 hours. Do not freeze. Transport promptly.
- Hemolysis max
- 50
- Lipemia max
- 50
- Icterus max
- 20
- TAT
- 24–72 hours
- Order
- routine
What is this test?
The Activated T Cells test measures the number and percentage of activated T lymphocytes (a type of white blood cell) in your blood. T cells are a crucial part of your immune system that help fight infections and abnormal cells. When T cells encounter a foreign substance (like a virus), they become 'activated' to mount an immune response. This test uses special laboratory techniques to identify and count these activated cells.
How is the test performed?
A healthcare provider will draw a blood sample from a vein in your arm. The sample is then sent to a laboratory where it is analyzed using flow cytometry or other免疫学 methods to detect specific markers (such as CD25, HLA-DR, or CD69) that indicate T cell activation. No special preparation is typically needed for this test.
Why might I need this test?
Your doctor may order this test if you have symptoms of an immune system disorder, such as frequent infections, unexplained fatigue, or autoimmune conditions. It is commonly used to monitor diseases like HIV/AIDS, evaluate immune deficiencies, assess autoimmune diseases (such as lupus or rheumatoid arthritis), and sometimes to monitor the effects of immunosuppressive therapies.
Reference range
Reference range: 10-30% of total lymphocytes (CD3+ HLA-DR+ activated T cells). Absolute count: 100-400 cells/μL. Ranges may vary by laboratory methodology and reference population.N/A
No special preparation required. Test can be performed without fasting. Avoid recent infections or immunosuppressive therapy when possible as these may affect results.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Do I need to fast before this test?
How long does it take to get results?
Is the test safe?
What do abnormal results mean?
Sources
- 1
- 2
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 10, 2026. · Read our editorial policy