Neutrophils: Abnormal levels of a type of white blood cell

Having a healthy number of neutrophils in the blood and bone marrow is crucial for the proper functioning of the immune system. Neutrophils are a type of white blood cell that helps heal damaged tissues and fight infections. Neutrophils naturally increase in response to infections, injuries, and other forms of stress. They decrease in response to severe or chronic infections, drug treatments and genetic disorders. Small changes in neutrophil or white blood cell levels are not normally a cause for concern, as long as they are temporary. If neutrophil or white blood cell levels change significantly for no apparent reason, or continue to rise or fall, medical testing is needed to determine the cause.

  • Function: Fight infection
  • Normal values
  • High levels of neutrophils in the blood
  • Range
  • Causes
  • Low levels of neutrophils in the blood
  • Range
  • Causes
  • Diagnosis and examinations
  • Treatment of neutropenia
  • Prevention of abnormal levels of white blood cell type


Function: Fight infection

The body produces neutrophils in the bone marrow. 55-70% of all white blood cells in the bloodstream are neutrophils. A normal overall level of white blood cells in the bloodstream for an adult is between 4,500 and 11,000 per cubic millimeter (mm3). When an infection or other source of inflammation is present in the body, neutrophils receive an alarm signal from special chemicals. The neutrophils then leave the bone marrow and travel through the bloodstream to the site of need. Unlike some other cells or blood components, neutrophils can enter tissues directly.

Normal values

The quantity and proportion of white blood cells (including neutrophils) in the bloodstream changes over time with age and other events, such as pregnancy. Although everyone’s normal range is slightly different, some common ranges include:

  • Newborn: 13,000 to 38,000 per mm3
  • Two-week-old baby: 5,000 to 20,000 per mm3
  • Adult: 4,500 to 11,000 per mm3
  • Pregnant woman (third trimester): 5,800 to 13,200 per mm3

 Obesity is a risk factor for neutrophilia / Source: Tobyotter, Flickr (CC BY-2.0)

High levels of neutrophils in the blood


In non-pregnant adults, a white blood cell count of more than 11,000 per mm3 is known as leukocytosis (an increased white blood cell count).


Neutrophilia (neutrophilic leukocytosis) is a condition in which an abnormally high level of neutrophils occurs in the blood. This usually happens due to infections or injuries. Blood levels of neutrophils also sometimes increase in response to:

  • burns
  • surgery
  • chronic myelogenous leukemia
  • eclampsia
  • a surgical removal of the spleen (splenectomy)
  • a heart attack
  • an infection (often bacterial)
  • an inflammatory bowel disease
  • an injury
  • a non-infectious inflammation
  • a pregnancy
  • physical or emotional stress
  • genetic conditions, such as Down syndrome
  • hepatitis (inflammation of the liver)
  • excessive exertion
  • rheumatoid arthritis (inflammation of joints and organs)
  • smoking cigarettes or sniffing tobacco
  • some medications, such as corticosteroids, beta-2 agonists, and epinephrine (adrenaline)
  • thyroiditis (inflammation and swelling of the thyroid gland)
  • vasculitis (inflammation of blood vessels)
  • obesity


Low levels of neutrophils in the blood


The lowest blood level limit for neutrophils in human blood is 1,500 per mm3. When a patient’s neutrophil level is low, it is known as neutropenia. The lower the number of neutrophils in the blood, the more severe neutropenia. Neutropenia levels are:

  • Mild neutropenia : 1,000 to 1,500 per mm3
  • Moderate neutropenia : 500 to 999 per mm3
  • Severe neutropenia : 200-499 per mm3
  • Very severe neutropenia : less than 200 per mm3



Neutropenia is the medical term for an abnormally low blood level of neutrophils. A drop in the number of neutrophils in the blood usually occurs when the body uses immune cells faster than it produces them or when the bone marrow does not produce them properly. This is due to:

  • congenital disorders, such as Kostmann syndrome and cyclic neutropenia
  • allergic conditions
  • aplastic anemia, when the bone marrow stops producing enough blood cells
  • autoimmune diseases, including rheumatoid arthritis
  • bacterial infections, such as tuberculosis (bacterial infection with lung problems)
  • bone marrow failure
  • blood poisoning
  • chronic benign neutropenia, which causes low cell levels for no apparent reason
  • an enlarged spleen (splenomegaly)
  • a weakened immune system
  • a vitamin B12 deficiency
  • severe congenital neutropenia, a group of conditions in which neutrophils cannot mature
  • serious or chronic bacterial infections
  • febrile neutropenia
  • hyperglycemia (increased blood sugar levels)
  • leukemia
  • medications: phenytoin and sulfa drugs, chemotherapy drugs
  • myelodysplastic syndromes (impaired production of blood cells)
  • myelofibrosis, a bone marrow disorder associated with a shortage of blood cells
  • radiotherapy that affects the bone marrow
  • toxins (poisons), such as benzenes and insecticides
  • viral infections, such as HIV/AIDS, influenza (flu), viral hepatitis A, viral hepatitis B, or viral hepatitis C

 A blood test is needed / Source: Frolicsomepl, Pixabay

Diagnosis and examinations

A blood test identifies changes in neutrophil counts. The doctor needs a medical history and asks the patient questions about lifestyle. A physical examination is also necessary. The doctor may also use more specific tests, depending on the possible cause of the increased or decreased neutrophils in the blood, such as:

  • a bone marrow biopsy
  • a CT scan
  • an x-ray of the chest (chest x-ray)
  • a urine test


Treatment of neutropenia

Severely high or low levels of white blood cells often require admission to the emergency department. Patients with severe neutropenia cannot defend themselves against an infection. The doctor treats the underlying cause to correct the abnormal levels of neutrophils.Support Supportive therapies, such as fluid administration and rest, are often also part of the treatment plan. If medications or procedures are causing the abnormal neutrophil levels, the doctor will stop them or adjust the treatment.Medicines restore neutrophil levels / Source: Stevepb, PixabayMedication Antibiotics treat bacterial infections, while antifungals help fight fungal infections. Certain medications reduce viral activity in viral infections. If the patient suffers from a chronic condition in which the adequate production or maturation of neutrophils is disturbed, medication is required. The doctor will then use colony-stimulating factors, corticosteroids (powerful anti-inflammatory drugs that suppress the immune system) or anti-thymocyte globulin, or else a bone marrow or stem cell transplant is required.Nutrition When a vitamin B12 deficiency is the cause of neutropenia, the patient should eat foods containing vitamin B12, such as eggs, poultry, meat, fish, milk and other dairy products.

Prevention of abnormal levels of white blood cell type

It is a good idea to have regular health check-ups with a doctor to stay healthy. Patients with further concerns about neutrophil counts or a medical condition should contact their physician.

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  • Neutropenia: Low neutrophil (white blood cell) count