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Absolute Count of CD3+ CD4+ T Cells (Peripheral Blood)

Published: August 9, 2026Updated: August 16, 2026

This test measures the number of specific immune cells in your blood, which helps assess your immune system’s strength and identify potential immune-related conditions.

Quick summary

["A lower count may signal weakened immunity or immune disorders; a higher count may need further evaluation for overactive immune responses."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
106910-3
Short code
BAL-CD4CD8
Synonyms
CD3+CD4+ Cells/CD3+CD8+ Cll BAL FC
Category
chemistry
Sample
serum
Container
Sterile BAL collection container; transfer to sterile polypropylene tube for flow cytometry. Keep at room temperature and process within 2-4 hours of collection for optimal viability.
Units
N/A
Ref low
1.5
Ref high
3.5
Critical range
0.5 N/A – 4 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–99 years
Method
flow-cytometry
CPT
86360
SNOMED
444100001
Specimen volume
Minimum 10-20 mL of BAL fluid required for flow cytometric immunophenotyping; optimal volume 30-50 mL. Saline aliquot used for lavage should be documented.
Stability
Process BAL fluid within 2-4 hours of collection for best lymphocyte viability. If delayed, store at 2-8°C for up to 12 hours. Do not freeze. Viability decreases significantly after 24 hours.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Matters

Your immune system relies on specialized white blood cells, including T-cells, to fight infections and regulate immune responses. CD3+ CD4+ T-cells are a key subset of these cells, often measured to diagnose or monitor conditions like HIV, autoimmune diseases, or immune deficiencies.

What to Expect During Testing

A simple blood draw is used to collect a small sample. The test analyzes the count of these specific immune cells, providing insights into your immune health without requiring fasting or special preparation.

Common Conditions Monitored

This test is often used in patients with HIV/AIDS to track immune function, in those with autoimmune diseases (e.g., rheumatoid arthritis, lupus) to monitor immune activity, or in individuals with suspected immune deficiencies.

Preparation and Timing

No special preparation is needed. Results are typically available within 24–48 hours, depending on lab processing times.

Reference range

CD4/CD8 ratio in BAL fluid: 1.5 - 3.5 (ratio). Normal BAL lymphocyte population shows CD4/CD8 ratio similar to or slightly higher than peripheral blood. A ratio >3.5 suggests sarcoidosis or hypersensitivity pneumonitis; a ratio <1.0 suggests opportunistic infections or certain interstitial lung diseases.N/A

Specimen: serum

Patient should fast for at least 4-6 hours prior to bronchoscopy. Bronchoscopy typically performed under sedation; inform physician of any anticoagulant use. No specific dietary restrictions beyond standard bronchoscopy preparation. Patient should sign informed consent for bronchoscopy procedure.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Interpretation and Next Steps

Short name

CD3/CD4 T-cell count

Frequently asked questions

What does a low CD3/CD4 count mean?
A low count may indicate a weakened immune system, potentially due to HIV infection, immune suppression from medications, or congenital immune disorders. Your healthcare provider will discuss next steps, such as further testing or treatment adjustments.
What if my count is high?
Elevated counts can sometimes signal overactive immune responses, though this is less common. High levels may warrant further evaluation for conditions like chronic inflammation or certain autoimmune disorders.
How often should I get this test?
Frequency depends on your medical condition. For example, HIV patients may get this test regularly to monitor immune recovery, while others may need it only if symptoms or test results suggest immune issues.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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