Neutrophils
Neutrophil Count
What this test measures
Neutrophils are a type of white blood cell that fight bacterial infections. They're the most common white blood cell and are your body's first defence against infection.
Understanding the numbers
Typical range: 2.0-7.5 × 10⁹/L
Neutrophils are part of your full blood count. They typically make up 40-70% of your white blood cells.
- Severe neutropenia: 0–0.5 × 10⁹/L
- Moderate neutropenia: 0.5–1.0 × 10⁹/L
- Mild neutropenia: 1.0–2.0 × 10⁹/L
- Normal: 2.0–7.5 × 10⁹/L
- Raised: 7.5–15 × 10⁹/L
- Markedly raised: 15–20 × 10⁹/L
Key numbers
- 0.5 × 10⁹/L — Below = high risk of serious infection
- 1.0 × 10⁹/L — Neutropenic sepsis threshold
- 2.0 × 10⁹/L — Lower limit of normal
- 1.5 × 10⁹/L — Benign ethnic neutropenia often 1.2-1.8
Neutropenic sepsis is defined (NICE CG151) as a neutrophil count of 0.5 or less in a person on cancer treatment with a temperature above 38°C (or other signs of infection). Some people of African or Middle Eastern ethnicity have baseline counts in the 1.2-1.8 range without increased infection risk — benign ethnic neutropenia.
Ranges can vary slightly between laboratories — your report may show slightly different numbers. This page does not read or interpret your result; your GP looks at it alongside your history and other tests.
What a higher-than-normal result can mean (Neutrophilia)
- Usually means your body is fighting a bacterial infection
- Can be raised by inflammation, stress, or smoking
- Steroid medications commonly raise neutrophils
- Rarely, can indicate a bone marrow problem
When not to wait
A very low neutrophil count with fever is a medical emergency. Don't wait for a GP appointment.
- Fever of 38°C or higher while on chemotherapy or known low neutrophils
- Uncontrollable shaking or feeling freezing cold
- Severe sore throat, mouth ulcers, or pus you cannot clear
- Pale, clammy skin with a racing pulse
- Confusion or drowsiness
- Any signs of infection (cough, urinary burning, tummy pain) with known low neutrophils
Call NHS 111 for urgent advice, or 999 if someone is seriously unwell.
Questions you could ask your GP
- Is my immune system working properly?
- Am I at higher risk of infections?
- Could any of my medications be causing this?
- Do I need to take any precautions?
Example stories
These are made-up examples to show how results are talked about in real appointments. They are not real patients.
Chemotherapy — fever after cycle 3
Charlotte is on chemotherapy for breast cancer. Twelve days after cycle 3 she spiked a fever of 38.6°C. Her neutrophils were 0.3 × 10⁹/L.
What the GP said: “This is neutropenic sepsis — a medical emergency. You need IV antibiotics within the hour. I'm sending you to A&E now with your chemo card.”
What happened next: Charlotte was given piperacillin-tazobactam within 45 minutes of arrival. She was admitted for four days; blood cultures grew E. coli. She recovered fully and her next chemo was delayed by one week.
Neutropenic sepsis is a time-critical emergency. If you're on chemotherapy and develop a fever, you must not wait — go to A&E or call your chemo helpline immediately. The 'door-to-antibiotic' target is one hour.
Routine check — persistently 'low' neutrophils
Tunde's neutrophil count was 1.4 × 10⁹/L — slightly below the 'normal' range. He had always had counts like this; he was well and had no unusual infections.
What the GP said: “This is benign ethnic neutropenia — some people of African heritage have baseline neutrophil counts slightly below the standard reference range. It's a variation, not a disease. We don't need to investigate and you have no extra infection risk.”
The standard neutrophil reference range is based on European populations. People of African, Afro-Caribbean or Middle Eastern ancestry often sit at 1.2-1.8 × 10⁹/L and this is normal for them.
Carbimazole-induced neutropenia
Beatrice was three weeks into carbimazole for Graves' disease. She developed a sore throat and mouth ulcers. Her neutrophils were 0.8 × 10⁹/L.
What the GP said: “Carbimazole can rarely cause your white cells to drop dangerously. Stop the carbimazole today. I'm referring you urgently to endocrinology and you need to watch closely for any fever — go to A&E if you develop one.”
What happened next: Beatrice's neutrophils recovered over two weeks off carbimazole. She was switched to propylthiouracil and later had radioiodine.
A small number of medicines (carbimazole, clozapine, some antibiotics) can drop the neutrophils suddenly. A sore throat, mouth ulcers or fever while on these drugs means urgent blood tests — the combination can lead to severe sepsis.
Bacterial pneumonia
Malcolm was unwell with a chest infection. His WBC was 22 and his neutrophils were 16 × 10⁹/L. A chest X-ray confirmed pneumonia.
What the GP said: “A high neutrophil count with a fever and productive cough points clearly to a bacterial infection. Let's start amoxicillin and clarithromycin today and review in 48 hours.”
What happened next: Malcolm improved steadily and his neutrophils normalised over ten days.
A marked neutrophil rise is the body's response to bacterial infection. Alongside CRP and the clinical picture, it helps decide whether antibiotics are needed.
Before you act on anything here
This page is general information, written to help you understand — it is not personal medical advice and it cannot tell you what is right for you. Talk to your own GP, pharmacist or nurse about your own health.
- Need help now but it's not an emergency? Call NHS 111 or use 111.nhs.uk.
- Emergency? Call 999 or go to A&E.