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CD3+ T Cell Count (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
107033-3
Short code
CD3CD7
Synonyms
CD3+CD7+ Cells NFr Spec FC
Category
chemistry
Sample
serum
Container
Heparinized tube (sodium or lithium heparin, green-top) preferred for flow cytometry; EDTA (lavender-top) tube may be acceptable; ACD (yellow-top) tube is an alternative for immunophenotyping. For serum specimens, use serum separator tube (SST, tiger-top or red-top with clot activator).
Units
N/A
Ref low
60
Ref high
85
Fasting
false
Population
adult
Sex
all
Age range
0–99 years
Method
flow-cytometry
CPT
86359 (T cells, total count); 86360 (T cells, absolute CD4 and/or CD8 count with ratio); additional CPT codes may apply for comprehensive immunophenotyping panels (e.g., 86355, 86357, 86361, 86367)
SNOMED
439127006 (CD3+CD7+ T lymphocyte); 271442001 (Flow cytometry procedure)
Specimen volume
Peripheral blood: 3-5 mL whole blood in anticoagulant tube; bone marrow: 1-3 mL; tissue/fluid specimens: as available. Minimum volume requirements vary by laboratory protocol.
Stability
Specimen should be processed within 24-48 hours of collection for optimal viability. Store at room temperature (18-25°C); do not refrigerate or freeze whole blood specimens as this may affect cell viability and marker expression. Actual stability depends on specimen type and laboratory-specific protocol.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–72 hours
Order
routine

What Are CD3+ T Cells?

CD3+ T cells are a subset of lymphocytes (a type of white blood cell) that play a critical role in your immune system. They help identify and destroy viruses, bacteria, and other foreign invaders while also managing immune responses to prevent overactivity.

Why Might This Test Be Done?

Your doctor may order this test to evaluate your immune system, diagnose conditions like HIV/AIDS, check for immune deficiencies, or monitor treatment effectiveness in diseases affecting T cells.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The blood is processed to separate the white blood cells, and the CD3+ T cells are counted using specialized laboratory techniques.

What Does a Result Mean?

Results are typically reported as an absolute count of CD3+ T cells per microliter (µL) of blood. Lower-than-expected counts may indicate immune suppression, while higher-than-expected counts could be seen in certain immune disorders.

Reference range

Reference ranges vary by laboratory and specimen type. CD3+CD7+ T-cell populations are typically evaluated as part of lymphocyte subset immunophenotyping. Generally, CD3+ T cells comprise 60-85% of total lymphocytes in peripheral blood, with the majority co-expressing CD7. Normal ranges should be established by each performing laboratory based on its instrument, reagents, and local population.N/A

Specimen: serum

No special patient preparation required. Fasting is not necessary. Patients should be well-hydrated. Recent transfusions, immunosuppressive therapy, chemotherapy, or hematopoietic stem cell transplantation may significantly affect results and should be documented.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

CD3 Cells

Frequently asked questions

How is this test different from a general white blood cell count?
This test specifically targets CD3+ T cells, a subset of white blood cells, rather than counting all white blood cells or other immune cell types. A general white blood cell count provides a broader overview of your immune system’s overall activity.
What does a low CD3+ T cell count mean in the context of HIV?
A low CD3+ T cell count in the context of HIV often reflects advanced disease or immune suppression. It’s commonly used to monitor disease progression and guide treatment decisions, such as starting antiretroviral therapy.
Can diet or supplements affect CD3+ T cell counts?
While diet and supplements may influence overall immune health, they generally do not directly affect CD3+ T cell counts. However, maintaining a balanced diet and good health can support immune function indirectly.
  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