Neutrophils in a blood test: normal range and results (NEU)

Neutrophils are one of the five types of white blood cell (leukocyte) and are made in the bone marrow. They make up the largest share of the white cells and are the immune system's first line of response to bacterial infections and inflammation — they travel to the damaged or infected tissue within a few hours and destroy pathogens. The amount of neutrophils is determined by a white cell differential (the differentiation of white blood cells), which is usually ordered together with a full blood count. The amount in the blood changes quickly — it can rise within a few hours of an infection starting, or because of stress or physical exertion, and it can fall during a viral illness, a bone marrow disease or while taking certain medicines. That is why a neutrophil result is always assessed together with the total white cell count, the other types of white cell (lymphocytes, monocytes, eosinophils, basophils) and the clinical picture, rather than on its own.

• When a full blood count has found a changed total white blood cell (leukocyte) count
• When a bacterial infection or inflammation is suspected — with a fever, weakness, or pain at the site of the infection
• When diagnosing or monitoring diseases of the blood, including leukaemia
• When monitoring the effect on blood formation of treatment that can suppress the bone marrow (for example chemotherapy)
• When a bone marrow disorder or an autoimmune disease is suspected
• As part of an assessment of general health together with a full blood count

Raised neutrophils (neutrophilia) most often indicate an acute bacterial infection or inflammation in the body. According to MedlinePlus, the causes also include autoimmune diseases (for example rheumatoid arthritis), trauma, acute stress and blood diseases such as leukaemia. The value is always assessed together with the clinical picture and the other blood values.

• An acute infection
• Inflammation
• Acute stress on the body
• Trauma
• Rheumatoid arthritis and other autoimmune diseases
• Leukaemia

What is usually assessed alongside a raised result:

• Whether there was an infection, inflammation or injury at the time — that is the most common cause
• The total white cell count and the other parts of the white cell differential (lymphocytes, monocytes) together with CRP
• Symptoms — a fever, pain, signs of inflammation
• When to repeat the test so that the change over time can be seen

Reduced neutrophils (neutropenia) can mean that the body is less well protected against bacterial infections. According to MedlinePlus, the causes include bone marrow diseases (for example aplastic anaemia), chemotherapy, flu or other viral infections, and severe bacterial infections that deplete the reserves of neutrophils.

• Aplastic anaemia or another bone marrow disease
• Chemotherapy
• Flu or other viral infections
• A severe bacterial infection that depletes the reserves of neutrophils

What is usually assessed alongside a reduced result:

• A full blood count and the whole white cell differential — to assess whether only the neutrophils are reduced, or all the white cells
• Any medicines taken recently, or treatment that can suppress the bone marrow
• Discussing the risk of infection with your doctor, especially if treatment that affects blood formation is planned
• When to seek help urgently — if you are being treated at the time with chemotherapy or another treatment that suppresses blood formation and your temperature rises, chills appear or you suddenly feel unwell: according to MedlinePlus, an infection during cancer treatment is an emergency, so contact your treating team immediately or go to an emergency department, without waiting for the next scheduled test
• When to repeat the test to assess the change over time