Neutrophils
The most common white blood cell and the body's first responder to bacterial infection.
Typical reference range
| Range | Unit |
|---|---|
| 1.5–7 | E9/l |
What Neutrophils measures
Neutrophils are the most common type of white blood cell and act as the immune system's first responders. When bacteria invade or tissue is damaged, neutrophils are among the first cells to arrive, engulfing microbes and clearing debris as part of the body's front-line defence. Because they turn over quickly and respond fast, their numbers can shift within hours of a challenge.
On a complete blood count (CBC), neutrophils are reported within the white-cell differential, usually as both an absolute count and a percentage of total white cells. Looking at the count and percentage together, alongside the other white-cell types, helps show how the immune system is responding at the moment the sample was taken.
What a high Neutrophils can mean
A high neutrophil count is called neutrophilia. It most commonly reflects an ongoing bacterial infection, since these cells surge to fight microbes, but many everyday factors can raise the number too.
- Inflammation or recent tissue injury, including after surgery
- Physical or emotional stress, and vigorous exercise
- Smoking
- Pregnancy
- Steroid (corticosteroid) medication
In most cases neutrophilia is a reactive response that reflects what the body is dealing with, rather than a diagnosis on its own. That is why the result is read in context, together with symptoms, the rest of the CBC, and how the picture changes over time. A clinician can judge whether a raised count is a passing reaction or something that warrants further attention.
What a low Neutrophils can mean
A low neutrophil count is called neutropenia. It can arise from a range of causes, and the significance depends on how low the count is and what else the blood picture shows.
- Some viral infections, which can temporarily lower neutrophils
- Certain medications, including chemotherapy
- Autoimmune conditions in which the body targets its own cells
- Vitamin deficiencies affecting cell production
- Bone-marrow problems that reduce output of new cells
Because neutrophils are central to fighting bacteria, very low counts can raise the risk of infection and may call for prompt attention. Neutropenia is interpreted alongside the rest of the CBC, any symptoms, and recent medication history, and is best reviewed with a clinician who can decide whether monitoring or further tests are needed.
Track your Neutrophils over time in Quanome — it reads your lab reports (PDF or photo) on your device, charts each marker against its range, and an AI coach explains what your trends mean alongside your Apple Health and DNA.