neutrophils Is the most important type of white blood cell (WBC) to fight infection. The absolute neutrophil count (ANC) is a test that assesses how many neutrophils are in the blood.
Your neutrophil count may be lower than normal for a number of reasons. Both illness and medication can cause low counts. For example, ANC decline may occur during cancer chemotherapy.
This article looks at the absolute neutrophil count test, its interpretation, and some reasons for a low ANC.
What is an ANC test?
The absolute neutrophil count in a healthy person is between 1,500 and 6,000. Your ANC can be found with a common blood test called a complete blood count (CBC). CBC gives your doctor the following numbers:
- Red blood cells, which carry oxygen and carbon dioxide in and out of your tissues
- White blood cells (WBCs), which help your body fight infections
- plateletssmall amounts of cellular material that help control bleeding
ANC is calculated by multiplying the total white blood cell count by the percentage of neutrophils.
ANC calculation example
If your total WBCs are 8,000 and 50% of your WBCs are neutrophils, your ANC is 4,000. This number is 8,000 times 0.50.
Modern blood counting tools can automatically find the number of each type of white blood cell and report the ANC. Lab professionals can also use microscopes to find numbers. This can be done to confirm findings or to provide more details.
Lab results may also include “bands” and “segments.” Bands are immature neutrophils, while segments are mature. Add these numbers to get the total.
Interpreting ANC Results
There may be a normal total WBC count but a low neutrophil count. Usually, however, when the neutrophil count is low, the WBC count is low. This is because neutrophils are usually the most abundant white blood cells. In most healthy people, they make up more than 50 percent of the white blood cell count.
neutropenia This happens when you have an abnormally low number of neutrophils in your blood. The extent of your neutropenia depends on how low your ANC is.
A healthy person’s ANC is between 2,500 and 6,000. The risk of infection may increase when the ANC falls below 1,000. When this happens, your doctor will want to monitor your counts closely. When your ANC is below 500, your risk of infection is much greater.
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 factors. This medicine helps promote the production of neutrophils.
If your ANC is low, your doctor will monitor you for signs of infection. You may also take antibiotics to help prevent infection.
What causes low ANC?
Neutrophils and other blood cells are made in your bone marrow. Life-saving cancer treatments, such as chemotherapy and radiation, may target fast-growing cells. Because this affects neutrophil production, a decrease in ANC may be an expected side effect. Low ANC can also be a sign of the disease itself, such as certain types of blood cancer.
Low ANC may also occur during treatment of other diseases.These include autoimmune diseases such as Rheumatoid arthritis. When you have an autoimmune disease, your immune system mistakes normal parts of your body for invaders.
One of the treatments for rheumatoid arthritis is Tocilizumab. This drug works by blocking the signals that cause inflammation in the body. It was associated with lower ANC, although this did not appear to be associated with severe infection.
There may be severe chronic primary neutropenia. This is a low ANC that occurs with no known cause. This condition is rare, but more common in women. Serious infections are uncommon, despite the low ANC. This is not well understood, but patients usually have an overall favorable outcome.
Cancer treatments can lead to low ANC. Low ANC can also be a sign of some cancers. Treatment of other diseases, such as autoimmune diseases, may also be associated with low ANC.
Low ANC symptoms
You don’t necessarily have obvious symptoms because your WBC count or ANC is low. That’s why it’s important to watch for signs of infection. Unfortunately, these signs may be less obvious as your ANC gets lower.
Here are some things to note:
- Difficulty breathing
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. People with a low ANC may not have redness or pus, but they may still be infected.
If your ANC is 1,000 or lower and you have a fever, your doctor may think there is an infection. When this happens, you may be given antibiotics right away before the source of the infection is discovered.
Your medical team will then try to narrow down the most likely causes from the list of possible pathogens. When they find the site and cause of the infection, they can choose treatments that target specific bacteria. This means you may switch to other antibiotics.
Low ANC itself doesn’t cause symptoms, but it does make you more susceptible to infection. Watch for any signs of infection, such as fever, redness and swelling, and difficulty breathing.
Neutrophils are white blood cells that help your body fight infection. The ANC test measures the number of neutrophils in the blood.
Your neutrophils may be low due to illness or treatment for conditions such as cancer or autoimmune disease. Some patients have low ANC for unknown reasons, although this is rare.
In most healthy people, more than 50% of the white blood cells are neutrophils. When your ANC is low, you may need to monitor closely for signs of infection.