What Is an Absolute Neutrophil Count (ANC)?

An absolute neutrophil count (ANC) is a test that assesses how many neutrophils are in your bloodstream. Neutrophils are the most important type of white blood cell (WBC) for fighting infection. This test may be ordered to ensure your immune system is working properly.

Your absolute neutrophil count may be outside the normal range for many reasons including stress, various conditions, and medical treatments.

This article explains the absolute neutrophil count test, how to interpret your results, as well as what it means if your ANC is high or low.

What Is an Absolute Neutrophil Count Test?

Your ANC can be found with a common blood test called the complete blood count (CBC). The CBC gives your healthcare provider your numbers for:

• Red blood cells (RBCs): Carry oxygen and carbon dioxide to and from your tissues
• White blood cells (WBCs): Help your body fight infection
• Platelets: Small bits of cellular material that help control bleeding

The ANC is found by multiplying the total white blood cell count by the percent that are neutrophils.

Blood counting tools can automatically find the number of each type of white blood cell and report the ANC. Lab professionals can also find the number using a microscope. This may be done to confirm findings or give more details.

Lab results may also include "bands" and "segs." Bands are immature neutrophils, while segs are mature. These numbers are added together to get the total absolute neutrophil count.

Interpreting ANC Results

Your results may indicate:

• Low absolute neutrophil count: Also called neutropenia, this occurs when you have levels of neutrophils that are less than 2,500 neutrophils per microliter of blood. If your levels are 1,000 or lower, you are at an increased risk of infection.
• Normal absolute neutrophil count: A healthy person has an ANC between 2,500 and 6,000 neutrophils per microliter of blood.
• High absolute neutrophil count: Also called neutrophilia, this occurs when you have levels that are higher than the absolute neutrophil count normal range.

WBC Count and Absolute Neutrophil Count Low

It’s possible to have a normal total WBC count but a low neutrophil count. Usually, though, the WBC count is low when the neutrophil count is low. This is because neutrophils are normally the most abundant white blood cells. In most healthy people, they make up more than 50% of the white blood cell count.

If your ANC is low or your healthcare provider expects it to drop, they may give you antibiotics to help prevent infection. You may also be given growth factor. This medicine helps boost your neutrophil production.

WBC Count and Absolute Neutrophil Count High

It's possible to have a normal or high WBC count with neutrophilia. However, neutrophilia often occurs with a high WBC count, especially if it is due to a recurring infection or long-term inflammation.

Why Is My Absolute Neutrophil Count Low?

Neutrophils and other blood cells are made in your bone marrow. Life-saving cancer therapies like chemotherapy and radiation may target rapidly growing cells.

Because this can impact the production of neutrophils, a drop in ANC may occur as a side effect. A low ANC can also be a sign of the disease itself, as in some types of blood cancer.

Low ANC may also happen:

• During treatment for other illnesses including autoimmune disorders, which occur when the immune system mistakenly attacks the body
• During one of the treatments for rheumatoid arthritis called tocilizumab, which isn't associated with serious infection and works by blocking a signal that causes inflammation in the body
• Due to chronic primary neutropenia, or low ANC that occurs with no known cause

Low ANC Symptoms

You won't necessarily have noticeable symptoms just because your WBC count or ANC is low. That's why it's important to watch for signs of infection.

Here are some things to look out for:

• Fever
• Chills
• Cough
• Trouble breathing
• Diarrhea
• Pain
• Fatigue

If you have a central venous access device, also called a central line or port, check for signs of infection. Look for redness, swelling, pain, or pus where the tube enters your body. A person with a low ANC might not have redness or pus, but could still have an infection.

If your ANC is 1,000 or lower and you have a fever, your healthcare provider may give you antibiotics right away. When your medical team finds the site and cause of the infection you may be switched to a different antibiotic that targets the specific germ.

What Does a High Absolute Neutrophil Count Mean?

A high absolute neutrophil count usually means something inflammatory is going on in the body. This may be due to:

• Infection, especially one that is recurring
• Long-term inflammatory conditions like rheumatoid arthritis, Crohn's disease, hepatitis, and ulcerative colitis
• Smoking cigarettes
• Exercising
• Experiencing stress
• Having surgery
• Medications such as corticosteroids, which are used to treat inflammation, as well as lithium, a type of mood stabilizer
• Neutrophilia that is hereditary

Summary

Neutrophils are a type of white blood cell that help your body fight infection. An ANC test measures the number of neutrophils in your blood. In most healthy people, more than 50% of white blood cells are neutrophils.

Your neutrophils might be low or high for various reasons including infection, certain types of cancer, surgery, long-term inflammatory conditions, certain medications and cancer treatments, as well as stress.