Skip to content

T-cell subset percentage by flow cytometry (serum/plasma)

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

This test measures the proportion of different types of T cells in your blood, which helps assess immune function and identify conditions affecting your immune system.

Quick summary

["Understanding your T-cell balance can guide treatment for immune disorders or infections."]

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

Key facts at a glance

LOINC
35459-7
Short code
T Cell XM SerPl-Imp
Synonyms
T Cell XM SerPl-Imp
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Matters

T cells are a key part of your immune system, helping your body fight infections and diseases. This test helps doctors see if your immune system is working as it should by looking at the numbers of different T-cell types in your blood.

What to Expect Before the Test

No special preparation is needed for this test. You’ll have a small needle inserted into your arm to draw a blood sample. The blood is then processed to analyze T-cell counts.

Common Uses of This Test

Doctors may order this test to diagnose or monitor conditions like HIV/AIDS, autoimmune diseases (e.g., lupus, rheumatoid arthritis), or immune deficiencies. It can also help track how well treatments are working.

What the Results Mean

Results show the percentage of different T-cell types (e.g., CD4+, CD8+, regulatory T cells). Abnormal levels may indicate immune system issues, but interpretation depends on clinical context and other tests.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

T-cell subset %

Frequently asked questions

What preparation should I follow before this test?
No special preparation is required. However, inform your doctor if you’re on blood-thinning medications or have a history of bleeding issues.
How long will it take to get my results?
Results are typically available within 1–3 business days, depending on lab processing times.
Can I eat or drink before this test?
You can eat and drink normally. Avoid alcohol for 24 hours before the test if instructed by your doctor.
  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