CD4 T-Cell Count (Peripheral Blood)
This test measures the number of CD4 cells (a type of white blood cell) in your blood. CD4 cells play a key role in helping your immune system fight infections.
["CD4 cells help protect your body from infections and diseases; low levels may indicate immune weakness."]
Key facts at a glance
- LOINC
- 44059-4
- Short code
- CD4NAIV
- Synonyms
- CD4+CD45RA+CD45RB+CD45RC+ Cells # Tiss
- Category
- chemistry
- Sample
- serum
- Container
- Sterile tissue collection container with RPMI 1640 or PBS transport medium; heparinized tubes acceptable for blood-derived specimens
- Units
- N/A
- Ref low
- 20
- Ref high
- 50
- Critical range
- 2 N/A – 7 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Flow cytometry with multi-color immunofluorescence panel using monoclonal antibodies against CD4, CD45RA, CD45RB, and CD45RC surface markers
- CPT
- 86360
- SNOMED
- 117617007
- Specimen volume
- Minimum 1-2 grams of tissue or 5-10 mL of tissue homogenate suspension; for blood, 5-10 mL in heparinized tube
- Stability
- Fresh tissue: process within 4-6 hours of collection at room temperature (18-25°C). For delayed processing, store at 2-8°C for up to 24 hours. Viable cells required; do not freeze.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
Why This Test Is Done
Your healthcare provider may order a CD4 count to monitor your immune system, especially if you have HIV, an organ transplant, or a condition that weakens your immune system. It can also help track how well your immune system is responding to treatment.
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 blood. This is usually quick and painless.
What the Results Mean
Results are typically reported as a count of CD4 cells per microliter (µL) of blood. Lower counts may suggest immune suppression, while higher counts may indicate a stronger immune response. Your healthcare provider will interpret results based on your medical history and needs.
Common Causes of Low CD4 Counts
Low CD4 counts can result from conditions like HIV infection, certain cancers, long-term use of steroids, or other immune-suppressing treatments. Chronic illnesses, malnutrition, or infections can also affect CD4 cell numbers.
Reference range
Reference ranges vary by tissue type and laboratory. For peripheral blood mononuclear cells, naive CD4+ T-cells (CD4+CD45RA+CD45RB+CD45RC+) typically represent 20-50% of total CD4+ T-cells. Tissue-specific reference ranges should be established by individual laboratories.N/A
No special preparation required. Patient should be well-hydrated. Recent immunizations, immunosuppressive therapy, or active infections may affect results and should be documented.
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 for my health?
How often should I get this test?
Can diet or lifestyle changes 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 17, 2026. · Read our editorial policy