T-cell subset count (natural killer cells) with flow cytometry

What Is NK Cell Count Used For?

NK cells are part of your body’s natural immune response. They help destroy viruses, bacteria, and abnormal cells like cancer cells. This test is often used to monitor immune function, especially in people with weakened immune systems, such as those undergoing chemotherapy or with certain immune disorders.

How Is the Test Performed?

A small blood sample is drawn from a vein in your arm. The blood is then analyzed using flow cytometry, a precise method that separates and counts different types of white blood cells, including NK cells.

Why Might You Need This Test?

Your doctor may order this test if you have symptoms of an immune disorder, receive treatments that suppress your immune system, or if you have a condition that affects NK cell function, such as HIV/AIDS, certain cancers, or autoimmune diseases.

What Do the Results Mean?

Results are typically reported as a count of NK cells per microliter of blood. While reference ranges can vary by lab, lower than expected counts may suggest immune suppression, while higher counts may indicate certain immune responses or conditions.