T-Cell Subset Quantification by Flow Cytometry (CD3+, CD4+, CD8+)

Why T-Cell Counts Matter in Immune Health

T cells are a critical part of your immune system, helping your body fight infections and diseases. This test measures three main types of T cells: CD3+ (total T cells), CD4+ (helper T cells), and CD8+ (cytotoxic T cells). Abnormal levels can indicate immune deficiencies, infections, or autoimmune conditions.

When This Test Is Ordered

Your healthcare provider may order this test if you have symptoms of a weakened immune system, such as frequent infections, unexplained weight loss, or fatigue. It’s also used before starting certain treatments, like chemotherapy or organ transplants, to monitor immune function.

What to Expect Before the Test

No special preparation is needed for this blood test. You’ll have a small needle inserted into your arm to draw a blood sample. The process usually takes a few minutes, and you may feel a brief pinch or discomfort.

What the Results Mean

Results show the absolute counts of each T-cell subset. Lower-than-expected counts may suggest immune suppression, while higher-than-expected counts could indicate conditions like certain cancers or chronic infections. Your provider will interpret these results in the context of your overall health.