Neutrophils are a type of white blood cell that helps heal damaged tissues and resolve infections. Neutrophil blood levels increase naturally in response to infections, injuries, and other types of stress. They may decrease in response to severe or chronic infections, drug treatments, and genetic conditions.
Neutrophils help prevent infections by blocking, disabling, digesting, or warding off invading particles and microorganisms. They also communicate with other cells to help them repair cells and mount a proper immune response.
The body produces neutrophils in the bone marrow, and they account for 55–70 percent of all white blood cells in the bloodstream. A normal overall white blood cell level in the bloodstream for an adult is somewhere between 4,500 and 11,000 per millimeters cubed (mm3).
When there is an infection or another source of inflammation in the body, special chemicals alert mature neutrophils, which then leave the bone marrow and travel through the bloodstream to the site in need.
Unlike some other cells or blood components, neutrophils can travel through junctions in the cells that line blood vessel walls and enter into tissues directly.
In this article, we look at the reasons for high or low neutrophil levels, how doctors can test these levels, and what normal neutrophil levels are for different groups.
There are many different reasons why a person may have higher or lower than normal levels of neutrophils in their blood.
Neutrophils are a type of white blood cell.
Having an abnormally high level of neutrophils in the blood is known as neutrophilic leukocytosis, also known as neutrophilia.
Some inflammatory conditions can increase neutrophil levels, including rheumatoid arthritis, inflammatory bowel disease, hepatitis, and vasculitis.
An abnormally low blood level of neutrophils is a condition called neutropenia.
A drop in neutrophil blood levels typically occurs when the body uses immune cells faster than it produces them or the bone marrow is not producing them correctly.
An enlarged spleen may also cause a decrease in neutrophil levels because the spleen traps and destroys neutrophils and other blood cells.
A laboratory specialist can evaluate a blood sample for white blood cell levels.
Doctors can identify changes in neutrophil levels from a blood test called a complete blood count (CBC) with differential, which identifies specific groups of white blood cells.
A doctor may order a CBC test when someone is experiencing a range of symptoms related to infection, chronic illness, and injury, such as fever, pain, and exhaustion. A nurse or technician will draw a small amount of blood from the arm and send it off for evaluation.
If the initial test shows a higher or lower number of white blood cells than normal, the doctor will likely repeat the test to confirm the results. If the initial results are confirmed, a doctor will perform a physical exam, ask questions about the person's lifestyle, and review their medical history.
If there is no apparent reason for changes in white blood cell levels, the doctor will order a more specific test. Laboratory specialists will look for specific white blood cells, such as immature neutrophils called myeloblasts. During an infection or chronic illness, these cells emerge from the bone marrow and mature in the blood instead of the bone marrow.
If myeloblasts or other white blood cells appear in significant levels in the blood, the doctor will request a bone marrow sample.
Bone marrow collection involves inserting a long needle into part of the pelvis near the back of your hip. The procedure can be very painful, and a doctor will typically take the sample in a hospital setting with at least a local anesthetic.
Experts will examine the bone marrow sample to see if neutrophils and other blood cells are developing correctly and are in regular supply.
Leukopenia is a condition where a person has a reduced white blood cell levels in their bloodstream. Learn about the causes, symptoms, and treatments here.
Changes in neutrophil levels are often a sign of more significant changes in white blood cell levels.
In non-pregnant adults, a white blood cell blood count over 11,000 per mm3 is known as leukocytosis, which is an elevated white blood cell count. Neutrophilic leukocytosis occurs when a person has over 7,000 per mm3 mature neutrophils in their bloodstream.
Minor changes in neutrophil or white blood cell levels are typically nothing to worry about as long as they are temporary. A raised white blood cell count often means the body is responding to infection, injury, or stress.
Some people have naturally lower levels of white blood cells and neutrophils than other people due to a range of factors, including congenital conditions.
If neutrophil or white blood cell levels are significantly altered for no apparent reason or remain raised or lowered, a doctor will order more tests to determine the cause.
Severely high or low levels of white blood cells often require emergency care and monitoring. People with severe neutropenia will have an inadequate defense against infection.
People with severe neutrophilia typically have a life-threatening type of infection or other inflammatory illness that requires treatment, such as cancer.
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The best way to correct abnormal neutrophil levels is to address and treat the underlying cause.
Antibiotics can treat bacterial infections, while antifungal medicine treats fungal infections. People can treat certain viral infections with medications that slow viral activity. Otherwise, supportive therapies, such as fluids and rest, may be part of the treatment plan.
People with altered neutrophil levels caused by medications or procedures may need to stop or adjust treatments.
People with severely low levels of neutrophils often require monitoring, antibiotic therapy, and hospitalization to reduce the risk of severe infection.
This period of intensive care helps keep people with weakened immune systems away from potentially harmful microorganisms. It also supports the body, giving it time to produce more white blood cells.
Try not to over-exercise or exercise beyond comfort levels.
Reduce stress levels and treat chronic or severe stress.
Seek medical attention for signs of infection, such as fever, weakness, fatigue, or pain, and treat infections exactly as prescribed.
Follow a healthful, balanced diet.
Treat chronic conditions, such as genetic or inflammatory conditions, exactly as prescribed.
However, people with only minor or mild changes in their neutrophil blood levels often show no symptoms and do not require any treatment.
Having a healthy number of neutrophils in the blood and bone marrow is crucial to the correct working of the immune system.
When neutrophil levels are higher or lower than usual for more than a short period, a doctor will order several tests to work out the underlying cause. People with significantly altered neutrophil levels may also require hospitalization to prevent infection and treat life-threatening conditions.
It is a good idea to have regular wellness checks at a doctor's office to stay on top of health. Anyone with concerns about their neutrophil count or any medical condition should talk to their doctor who will be able to answer questions they may have.
Huizen, Jennifer. "What are neutrophils and what do they do?." Medical News Today. MediLexicon, Intl., 13 Dec. 2018. Web.