CD3+ T Cell Count (Absolute)

What Are CD3+ T Cells?

CD3+ T cells are a subset of lymphocytes (a type of white blood cell) that play a central role in the immune system. They help identify and destroy pathogens like viruses and bacteria, as well as regulate other immune responses. CD3 is a protein marker found on all T cells, making this test useful for assessing overall T cell activity.

Why Might You Need This Test?

Doctors may order a CD3+ T cell count to evaluate immune function, diagnose conditions like immunodeficiency, or monitor treatment responses in diseases such as HIV, autoimmune disorders, or certain cancers. It can also help assess how well your immune system is responding to infections or medications.

How Is This Test Performed?

A blood sample is drawn from a vein, usually in your arm. The sample is then analyzed in a lab to count the number of CD3+ T cells present. This test is typically done using flow cytometry, a technique that separates and counts different types of blood cells based on their markers.

What Do Results Mean?

Results are usually reported as a count of CD3+ T cells per microliter (cells/µL) of blood. Lower than expected counts may indicate immune deficiencies or conditions affecting T cell production or function. Higher counts may sometimes be seen in certain infections or inflammatory states, but this is less common.