Lymphocyte Subset Count: CD3+, CD4+, CD8+ Cells
This test measures specific types of white blood cells (lymphocytes) in your blood, focusing on CD3, CD4, and CD8 markers that help identify immune cell populations.
["This test helps assess immune health and identify immune-related conditions."]
Key facts at a glance
- LOINC
- 106912-9
- Short code
- BALCD4
- Synonyms
- CD3+CD4+ Cells/lymph NFr BAL FC
- Category
- chemistry
- Sample
- serum
- Container
- Sterile, non-preservative-containing collection container for BAL fluid; kept on wet ice or refrigerated at 2–8 °C during transport. Transport to flow cytometry laboratory in sterile conical tube within 24 hours.
- Units
- N/A
- Ref low
- 30
- Ref high
- 70
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- flow-cytometry
- CPT
- 88184
- SNOMED
- 395125005
- Specimen volume
- Minimum 10–20 mL of BAL fluid is preferred for adequate cell yield; larger volumes (≥30 mL) improve accuracy.
- Stability
- Specimen should be processed within 2–4 hours of collection for optimal viability and accurate lymphocyte subset enumeration. If delay is unavoidable, store at 2–8 °C; viability declines significantly beyond 24 hours.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What Does Each Marker Represent?
CD3 is a marker found on most immune cells, including T-cells. CD4+ T-cells are a subset of T-cells that help regulate immune responses, while CD8+ T-cells are involved in killing infected or cancerous cells. Together, these markers provide insight into your immune system’s structure and function.
Why Might You Need This Test?
Your doctor may order this test to evaluate immune function, diagnose conditions like HIV/AIDS, or monitor treatment responses in diseases affecting the immune system.
Sample Collection and Preparation
A small blood sample is drawn from a vein, typically in your arm. The blood is processed to separate and count the specific lymphocyte subsets. No special preparation is needed, but fasting may be advised depending on additional tests.
Common Uses and Conditions
This test is often used in diagnosing and managing immune disorders, infections, and cancers. It helps determine immune cell balance, which can be disrupted in conditions like autoimmune diseases, infections, or after certain treatments.
Reference range
Typically reported as % of lymphocytes; in healthy non-smoking adults, BAL CD3+CD4+ lymphocytes generally represent 30–70% of total lymphocytes with a CD4/CD8 ratio ≥1.5. In sarcoidosis and other granulomatous disorders, CD4/CD8 ratio is often elevated (>3.5). Clinical interpretation should consider clinical context and institutional reference values.N/A
Patient should fast for at least 6 hours prior to bronchoscopy if sedation or anesthesia is planned. Inform the bronchoscopy team of anticoagulant use, allergies, and recent respiratory infections. No specific fasting required for the flow cytometry assay itself once BAL specimen is obtained.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Lymphocyte Subset Panel
Frequently asked questions
How Long Does It Take to Get Results?
What Does a Low or High Count Mean?
Do I Need to 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