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T-cell subset percentage in peripheral blood (CD3+, CD4+, CD8+, CD19+, CD16+/56+ cells)

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

This test measures the proportions of different types of immune cells in your blood, which helps assess immune function and identify immune-related conditions.

Quick summary

["Understanding your immune cell balance can help diagnose or monitor immune disorders."]

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

Key facts at a glance

LOINC
25039-9
Short code
CT Ltd Unsp region
Synonyms
CT Ltd Unsp region
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ct
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your doctor may order this test if you have symptoms of an immune disorder, such as frequent infections, unusual fatigue, or unexplained weight loss. It can also be used to monitor immune responses before or after treatments like chemotherapy or immune-modifying therapies.

What to Expect Before the Test

No special preparation is needed. You may have a simple blood draw, often done in a doctor’s office or lab. If you’re taking blood thinners, let your doctor know beforehand.

What the Results Mean

Results show the percentage of different T-cell types (e.g., CD4+ helper cells, CD8+ cytotoxic cells) and other immune cells. Abnormal levels may indicate conditions like HIV, autoimmune diseases, or immune deficiencies.

Common Conditions Linked to These Results

Low or high percentages of certain T-cell subsets can signal immune system imbalances. For example, low CD4+ cells are often linked to HIV progression, while elevated CD8+ cells may suggest chronic infections or certain cancers.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

T-cell subset analysis

Frequently asked questions

What does a ‘normal’ result mean for me?
A ‘normal’ result means your immune cell proportions fall within expected ranges for your age and health. However, ‘normal’ doesn’t always mean healthy—your doctor will interpret results in the context of your symptoms and medical history.
Can this test detect all immune disorders?
No, this test provides a snapshot of immune cell proportions but isn’t a complete immune profile. Additional tests (like viral load or antibody checks) may be needed for a full diagnosis.
How often should I get this test?
Frequency depends on your condition. Doctors may recommend regular checks if you have an immune disorder, are on long-term treatments, or have a history of immune-related 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