Definition

Neutropenia (noo-troe-PEE-nee-uh) occurs when you have too few neutrophils, a type of white blood cells. While all white blood cells help your body fight infections, neutrophils are important for fighting certain infections, especially those caused by bacteria.

You probably won't know that you have neutropenia. People often only find out when they've had blood tests done for other reasons.

A single blood test showing low levels of neutrophils doesn't necessarily mean you have neutropenia. These levels can vary from day to day, so if a blood test shows you have neutropenia, it needs to be repeated for confirmation.

Neutropenia can make you more vulnerable to infections. When neutropenia is severe, even the normal bacteria from your mouth and digestive tract can cause serious illness.