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CD3+ T Cell Count in Whole Blood (Absolute)

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

This test measures the number of CD3+ T cells in your blood, which are a type of white blood cell important for immune function.

Quick summary

["CD3 T cells help fight infections and regulate immune responses."]

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

Key facts at a glance

LOINC
101645-0
Short code
CD3+CD8+ Cells p COVID NuclCap # Bld
Synonyms
CD3+CD8+ Cells p COVID NuclCap # Bld
Category
coagulation
Sample
whole-blood
Container
Lavender-top (EDTA)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
3 mL
Stability
Room temperature: 4h, Refrigerated: 24h
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
4–24 hours
Order
routine

What Is CD3 T Cell Count Used For?

Doctors may order this test to evaluate your immune system, especially if you have symptoms like frequent infections, unexplained fatigue, or conditions like HIV, autoimmune diseases, or certain cancers. It can also help monitor treatment responses in patients receiving immune-modulating therapies.

How Is the Test Performed?

A small blood sample is drawn from a vein, typically in your arm. The blood is then analyzed in a lab to count the CD3+ T cells. This process usually takes a few hours and is done using a specialized blood test called flow cytometry.

What Does a Low or High CD3 T Cell Count Mean?

A low CD3 T cell count may indicate a weakened immune system, which can be due to conditions like HIV/AIDS, certain cancers, or treatments that suppress the immune system. A high count might suggest overactive immune responses or certain infections.

When Might You Need This Test?

You might need this test if you have symptoms of immune dysfunction, are undergoing treatment for an immune-related condition, or if your doctor suspects an issue with your T cells.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: CD3+ T Cells and Immune Health

Short name

CD3 T Cell Count

Frequently asked questions

Why might my doctor want to check my CD3 T cell count?
Your doctor may check your CD3 T cell count to diagnose or monitor conditions affecting your immune system, such as HIV, certain cancers, or autoimmune diseases. It can also help determine how well your immune system is responding to treatments like chemotherapy or immune-suppressing medications.
What are typical results, and when should I be concerned?
There are no standard reference ranges provided here, as they can vary by lab and individual health. Your results will be interpreted by your healthcare provider based on your overall health and medical history. If your results are outside expected ranges, further evaluation may be needed.
Can I influence my CD3 T cell count?
While you can’t directly control your CD3 T cell count, maintaining a healthy lifestyle—including a balanced diet, regular exercise, and avoiding smoking—can support overall immune function. Certain medications and chronic illnesses can also impact T cell levels, so it’s important to follow your doctor’s advice.
  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