CD4 T-Cell Count (Absolute)
This test measures the number of CD4 T-cells, a type of white blood cell important for immune function. CD4 cells help the body fight infections and respond to vaccines.
["CD4 cells are critical for immune health; low counts may signal immune weakness."]
Key facts at a glance
- LOINC
- 17161-1
- Short code
- CD47
- Synonyms
- CD47 Cells NFr Bld
- Category
- chemistry
- Sample
- whole-blood
- Container
- EDTA (lavender-top) or heparin (green-top) anticoagulant tube suitable for flow cytometry
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Flow cytometry
- CPT
- 86356
- SNOMED
- 117617002
- Specimen volume
- 3-5 mL of whole blood; minimum 1 mL for pediatric samples
- Stability
- Process within 24 hours of collection at room temperature (18-25°C); do not refrigerate as this may affect cell surface marker expression
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 24–72 hours
- Order
- routine
Why Is This Test Done?
Your doctor may order a CD4 count to monitor immune function, especially if you have HIV, an autoimmune condition, or are undergoing treatments that affect immunity. It helps track how well your immune system is responding to treatment or managing chronic illnesses.
What Does a Low or High Count Mean?
A low CD4 count (below normal) may indicate a weakened immune system, which can increase the risk of infections or certain cancers. A very high count (rarely seen) might suggest overactive immune responses or certain blood disorders.
How Is This Test Performed?
A small sample of blood is drawn from a vein, usually in your arm. The blood is then analyzed in a lab to count the number of CD4 T-cells.
What Are Common Results?
Results are typically reported as a count of CD4 cells per microliter (cells/µL). Normal ranges can vary slightly by lab, but generally, healthy adults have counts between 500 and 1,500 cells/µL. Your doctor will interpret results based on your health status and medical history.
Reference range
Results reported as percentage of CD47-positive cells or absolute count; reference ranges established by individual laboratory based on flow cytometry analysis. CD47 is broadly expressed on most hematopoietic cells.N/A
No special patient preparation required. Sample should be processed promptly to maintain cell viability for accurate flow cytometric analysis.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
CD4 Cell Count
Frequently asked questions
What factors can affect my CD4 count?
How often should I get this test?
Can I prepare for 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