Neutrophil Count (Absolute Neutrophil Count, ANC)

What Neutrophils Do in Your Body

Neutrophils are a type of white blood cell that plays a critical role in defending your body against infections caused by bacteria. They move quickly to areas where bacteria are present and release chemicals to destroy them. High neutrophil counts may indicate an active infection, inflammation, or other immune responses, while very low counts can signal conditions like chronic infections, autoimmune diseases, or certain cancers.

When Might You Need This Test?

Your doctor may order an ANC test if you have symptoms like frequent infections, fever, fatigue, or if you’re undergoing treatment that could affect your immune system (e.g., chemotherapy, certain medications). It’s also used to monitor conditions like leukemia, HIV, or other immune disorders.

How Is the Test Done?

A small amount of blood is drawn from a vein, usually in your arm. The sample is then analyzed in a lab to count the number of neutrophils.

What to Expect Before or After the Test

There are usually no special preparations needed. You may feel slight discomfort or bruising at the injection site, but this is normal. If you’re on blood-thinning medication, let your doctor know before the test.