CD8 T-Cell Count (Per Microliter) in Whole Blood
This test measures the number of CD8+ T cells, a type of immune cell that helps fight viruses and cancer. It’s often used to check immune function or monitor conditions like HIV, lymphoma, or other immune-related disorders.
["CD8+ T cells are key defenders in your immune system; this test helps track their levels for health or disease management."]
Key facts at a glance
- LOINC
- 38241-6
- Short code
- CD8CD95
- Synonyms
- CD8+CD95+ Cells # Bld
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA (lavender/purple-top) blood collection tube for flow cytometry analysis
- Units
- N/A
- Ref low
- 50
- Ref high
- 400
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Flow cytometry using fluorescently labeled monoclonal antibodies against CD8 and CD95 surface markers, with absolute count determination using counting beads or volumetric measurement
- CPT
- 86359
- SNOMED
- 122575007
- Specimen volume
- 3-5 mL whole blood in EDTA tube; minimum 1 mL required for pediatric samples
- Stability
- Specimen should be processed within 24-48 hours of collection when stored at room temperature (18-25°C); refrigerated storage may reduce viability of certain cell populations
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 24–72 hours
- Order
- routine
Why This Test Matters
CD8+ T cells are a critical part of your immune system’s ability to recognize and destroy infected cells or cancerous cells. This test helps doctors assess immune health, especially in conditions like HIV, where CD8 counts can change over time. It may also be used in cancer treatment to monitor immune responses.
What to Expect Before the Test
No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw a small amount of blood. The process usually takes a few minutes, and you can resume normal activities afterward.
What the Results Mean
Results show the number of CD8+ T cells in your blood. While reference ranges vary by lab, lower than expected counts may suggest immune suppression, infections, or certain cancers. Higher-than-expected counts could indicate autoimmune conditions or other immune disorders. Your doctor will interpret results in the context of your overall health.
Common Uses of This Test
Doctors may order this test to evaluate immune function, monitor HIV progression, assess lymphoma or other cancers, or check for immune-related side effects from treatments like chemotherapy or steroids.
Reference range
Reference ranges vary by laboratory and instrument platform; typical adult reference range is approximately 50-400 cells/μL (absolute count), representing roughly 10-30% of total lymphocytes; consult laboratory-specific reference intervalN/A
No special patient preparation required; fasting is not necessary
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CD8 T-Cell Count
Frequently asked questions
What causes CD8+ T-cell counts to change?
How often should I get this test?
Can diet or lifestyle affect CD8+ T-cell counts?
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