CD4 T-Cell Count (Per Microliter) in Whole Blood
This test measures the number of CD4 cells (a type of white blood cell) in your blood, which helps assess your immune system strength, particularly in conditions like HIV.
["CD4 cells are key to fighting infections; lower counts may signal immune weakness."]
Key facts at a glance
- LOINC
- 26569-4
- Short code
- CD4CD29
- Synonyms
- CD4+CD29+ Cells # Bld
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA (purple/lavender-top) blood collection tube; alternatively ACD (yellow-top) tube
- Units
- N/A
- Ref low
- 200
- Ref high
- 1200
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 1–99 years
- Method
- Flow cytometry (immunophenotyping using fluorescently labeled monoclonal antibodies against CD4 and CD29 surface markers)
- CPT
- 86359 (T cells, total count); 86360 (T cells, absolute CD4 and CD8 count, including ratio); 86361 (T cells, absolute CD4 count)
- SNOMED
- 39083005 | 269795007
- Specimen volume
- 3-5 mL whole blood (pediatric: 1-2 mL minimum)
- Stability
- Stable for 24-48 hours at room temperature (18-25°C); must be processed within 30 hours for optimal lymphocyte viability. Do not refrigerate or freeze whole blood sample.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why This Test Matters
CD4 cells are part of your immune system’s defense. They help your body fight infections and diseases. This test is especially important for people with weakened immune systems, such as those with HIV or undergoing certain treatments.
What to Expect Before the Test
No special preparation is needed. You may have a small needle inserted into your arm or hand to draw a blood sample. The process is quick and usually painless. If you’re nervous, let your healthcare provider know.
What the Results Mean
Results are reported as the number of CD4 cells per microliter of blood. While specific ranges vary by lab, lower counts may indicate a stronger need for immune support or monitoring.
Common Uses of This Test
Doctors use this test to monitor immune health, especially in people with HIV, cancer, or other conditions that weaken the immune system. It helps track how well treatments are working or if you need additional support.
Reference range
Reference ranges vary by laboratory; CD4+CD29+ cell counts typically range from 200-1200 cells/µL in healthy adults. Age-adjusted pediatric ranges differ. Consult laboratory-specific reference intervals.N/A
No special preparation required. Patient should be well-hydrated. Avoid recent blood transfusions if possible, as they may affect lymphocyte subset analysis.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CD4 Count
Frequently asked questions
What causes CD4 cell counts to change?
How often should I get this test?
Can diet or lifestyle affect CD4 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