Neutrophil Percentage (NEU%): Normal Range & Meaning

What Is Neutrophil Percentage (NEU%)?

When you look at a complete blood count (CBC) report, the NEU% — or neutrophil percentage — tells you what fraction of your white blood cells are neutrophils. Neutrophils are the most abundant type of white blood cell and act as the body's first line of defence against bacterial and fungal infections.

In my clinical practice, I often see patients who are puzzled by the numbers on their blood test. The NEU% is reported both as an absolute count (NEU#) and as a percentage. The percentage helps us understand the relative distribution of white blood cell types, which can shift dramatically during illness.

Why Is the NEU% Measured?

Doctors use NEU% to evaluate infection, inflammation, and immune system health. It is also a key part of the differential white blood cell count, which breaks down the five major types of white cells: neutrophils, lymphocytes, monocytes, eosinophils, and basophils.

A raised NEU% often points toward a bacterial infection or acute stress, while a low NEU% may raise concerns about viral infections, bone marrow problems, or medication side effects. However, the percentage alone can be misleading if the total white blood cell count is abnormal, which is why the absolute neutrophil count (ANC) is often more reliable.

Reference Ranges for NEU% (Neutrophil Percentage)

Normal values vary slightly between laboratories, but the typical reference range for adults is 40–60% of total white blood cells. Children and pregnant women have different reference intervals due to physiological changes.

Always check the reference range provided by your laboratory. These numbers are a guide, not a diagnosis.

What Does a High Neutrophil Percentage Mean?

A NEU% above the normal reference range is called neutrophilia. In my patients, the most common cause is an acute bacterial infection — think pneumonia, urinary tract infection, or appendicitis. But it can also occur after surgery, trauma, burns, or during a heart attack due to the stress response.

Other Causes of High NEU%

• Chronic inflammation (e.g., rheumatoid arthritis)
• Medications such as corticosteroids or lithium
• Smoking
• Myeloproliferative disorders (rare)

If your NEU% is high and you have fever or pain, your doctor will likely start looking for an infection. Isolated high NEU% without symptoms may be a sign of stress or a lab error.

What Does a Low Neutrophil Percentage Mean?

A low NEU% — called neutropenia — can leave you vulnerable to infections. I often see this in patients undergoing chemotherapy, which suppresses bone marrow production. Viral infections such as influenza or COVID-19 can also temporarily lower neutrophil percentage because lymphocytes dominate the differential.

Causes of Low NEU%

• Severe bacterial infections (overwhelming sepsis can consume neutrophils)
• Bone marrow disorders (e.g., aplastic anaemia, leukaemia)
• Autoimmune neutropenia
• Vitamin B12 or folate deficiency
• Certain medications (antipsychotics, antibiotics)

A low NEU% on its own may not be alarming if the total white cell count is normal. However, an absolute neutrophil count (ANC) below 1.0 × 10⁹/L requires urgent attention, especially if you have a fever.

Neutrophil Percentage During Pregnancy

Pregnancy brings a natural rise in NEU% due to hormonal changes and increased blood volume. By the third trimester, it is common to see neutrophil percentages of 60–80%. This is a normal physiological adaptation and not a sign of infection unless accompanied by fever or other symptoms.

In my experience, many expectant mothers worry when they see a high NEU% on their prenatal blood tests. Reassuring them that this is expected helps reduce unnecessary anxiety.

How to Interpret Your NEU% Result

Never interpret NEU% in isolation. The complete blood count with differential provides context. For example, a high NEU% with a high total white cell count (leukocytosis) strongly suggests infection. A low NEU% with a normal total white count may indicate a viral process.

The LOINC code for neutrophil percentage is 26464-8 (Neutrophils/100 leukocytes). Your lab report may list it as "NEU%" or "% Neutrophils".

If your value is outside the reference range, speak with your doctor. They will correlate it with your symptoms, medical history, and other lab results to determine the next steps.