CD4 T-Cell Count (Absolute)
This test measures the number of CD4 T-cells in your blood, a type of white blood cell critical for immune function. CD4 cells help fight infections and are often monitored in people with weakened immune systems.
["CD4 cells are key to your immune health—low counts may signal immune suppression."]
Key facts at a glance
- LOINC
- 107034-1
- Short code
- CD4CD8
- Synonyms
- CD4+CD8+ Cells NFr Spec FC
- Category
- chemistry
- Sample
- serum
- Container
- EDTA (purple-top) anticoagulant tube for whole blood flow cytometry; alternatively, heparinized (green-top) tube may be acceptable per laboratory protocol
- Units
- N/A
- Ref low
- 0
- Ref high
- 3
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- flow-cytometry
- CPT
- 86360
- SNOMED
- 395124003
- Specimen volume
- 1-3 mL of whole blood; minimum 0.5 mL for pediatric samples
- Stability
- Specimen should be processed within 24-48 hours of collection when stored at room temperature (18-25°C). Do not refrigerate or freeze whole blood samples as this may cause cell loss and altered antigen expression. EDTA samples are stable up to 30 hours at room temperature.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–48 hours
- Order
- routine
Why This Test Matters
CD4 cells are part of your immune system’s defense against infections. They play a vital role in helping your body fight viruses, bacteria, and other pathogens. Low CD4 counts can indicate immune dysfunction, which may increase your risk of infections or certain diseases.
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 blood, similar to a routine blood draw. If you’re on blood thinners or have a history of bleeding issues, let your healthcare provider know.
What the Results Mean
Results are typically reported as a count of CD4 cells per microliter (cells/µL) of blood. While reference ranges vary by lab, very low counts (often below 200 cells/µL) may signal immune suppression, which can affect your ability to fight infections.
Common Reasons for Testing
This test is commonly ordered for people with HIV/AIDS to monitor immune health, those with weakened immune systems (e.g., due to chemotherapy or organ transplants), or individuals with chronic illnesses that may affect immunity.
Reference range
CD4+CD8+ dual-positive T lymphocytes typically represent <3% of total lymphocytes in healthy individuals. Reference values vary by age; consult laboratory-specific reference interval. Values are reported as a percentage (%) or absolute count (cells/µL) depending on reporting laboratory.N/A
No special preparation required. Patient should be well-hydrated. Inform laboratory of recent blood transfusions, immunosuppressive therapy, or vaccination, which may transiently alter lymphocyte subpopulations.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CD4 Count
Frequently asked questions
What does a low CD4 count mean?
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 16, 2026. · Read our editorial policy