⚠️ Educational only. LabPlain does not provide medical advice or diagnosis. Always discuss your specific results with your healthcare provider.
What this test measures
Neutrophils are your most abundant white blood cell and your immune system's first responders. When bacteria, fungi, or other pathogens enter your body, neutrophils are the first cells to rush to the site — they engulf and destroy the invaders in a process called phagocytosis.
The neutrophil count on your CBC (Complete Blood Count) tells your doctor how many of these infection-fighting cells are circulating in your blood. It can be reported as an absolute number (ANC — Absolute Neutrophil Count) or as a percentage of your total white blood cells.
Doctors order this test to evaluate infections, immune system disorders, the effects of chemotherapy, or unexplained fatigue and illness.
Normal reference range
1.8–7.7 × 10³/µL | 40–70% of total white blood cells
The absolute neutrophil count (ANC) is the more clinically important number. An ANC below 1.5 is called neutropenia; below 0.5 is considered severe neutropenia and carries serious infection risk.
Reference ranges vary slightly between labs. Always compare your result to the range printed on your own lab report.
⚠️ ANC vs. Percentage
Your report may show neutrophils as a percentage (e.g., 58%) or as an absolute count (e.g., 4.2 × 10³/µL). The absolute count is more meaningful — a percentage alone can be misleading if your total white cell count is abnormal. Ask your doctor which number they're focusing on.
What your result might indicate
↑ If High
High neutrophils (neutrophilia) usually signals your body is actively fighting a bacterial infection. It can also be caused by physical stress, steroid medications, smoking, heart attack, or inflammatory conditions.
↓ If Low
Low neutrophils (neutropenia) means reduced ability to fight infection. Causes include viral infections, chemotherapy, autoimmune conditions, bone marrow disorders, or certain medications.
Symptoms associated with abnormal neutrophils
↑ High Neutrophil Symptoms
Fever and chills
Pain or swelling at infection site
Fatigue and body aches
Redness or warmth in tissues
Pus or discharge from wounds
Rapid heart rate
↓ Low Neutrophil Symptoms
Frequent or recurring infections
Infections that won't heal
Fever with no obvious cause
Mouth sores or ulcers
Skin infections or abscesses
Extreme fatigue
Common causes of abnormal neutrophils
What can raise neutrophils?
Bacterial infections are the most common cause of elevated neutrophils — your bone marrow ramps up production to fight the threat. Other causes include physical stress (surgery, trauma, heart attack), steroid medications like prednisone, smoking, chronic inflammatory conditions like rheumatoid arthritis, and in rare cases, blood cancers like chronic myeloid leukemia (CML).
Temporary spikes are also normal after intense exercise, emotional stress, or even epinephrine (adrenaline) release — these usually resolve within hours.
What can lower neutrophils?
Viral infections (including the flu, COVID-19, and HIV) are a common cause of temporarily low neutrophils. Chemotherapy and radiation therapy destroy fast-dividing cells including neutrophils, which is why cancer patients are closely monitored for neutropenia. Autoimmune conditions like lupus, certain antibiotics and other medications, and bone marrow diseases like aplastic anemia can also suppress neutrophil production.
Tests often ordered alongside neutrophils
Neutrophils are part of your CBC differential. Your doctor may also look at:
Total WBC (White Blood Cell Count) — the big picture count that neutrophils are part of
Lymphocytes — another white blood cell type; a high lymphocyte-to-neutrophil ratio can suggest viral infection
CRP (C-Reactive Protein) — an inflammation marker that rises with bacterial infections
Blood cultures — ordered when serious bacterial infection (sepsis) is suspected
Bone marrow biopsy — if neutropenia is severe or unexplained, to check bone marrow production
What to do next
A single abnormal neutrophil count rarely tells the whole story. Always look at this number alongside your total WBC and other CBC values. Mildly abnormal results are often temporary — caused by a recent illness, medication, or stress. Your doctor will consider your full clinical picture before deciding if follow-up testing is needed.
Questions to ask your doctor
01Is my absolute neutrophil count (ANC) within normal range, or just the percentage?
02Could any medications I'm taking be affecting my neutrophil count?
03Do I need a repeat CBC to see if this result is a trend or a one-time fluctuation?
04Should I be concerned about infection risk given my current count?
05Do my other CBC values — lymphocytes, WBC, platelets — support or change how you're interpreting this?
06Is a referral to a hematologist necessary?
Frequently asked questions
What is an absolute neutrophil count (ANC)?
The ANC is calculated by multiplying your total WBC count by the percentage of neutrophils. It gives a more precise picture of your infection-fighting capacity than the percentage alone. An ANC below 1,500 is neutropenia; below 500 is severe and carries high infection risk.
Can a viral infection cause low neutrophils?
Yes — many viral infections temporarily suppress neutrophil production or cause neutrophils to move out of the bloodstream into tissues. This is why neutrophil counts are often low during the flu, COVID-19, or other viral illnesses. They typically recover on their own as the infection resolves.
How serious is neutropenia?
It depends on the severity and cause. Mild neutropenia (ANC 1,000–1,500) often requires monitoring but not urgent treatment. Severe neutropenia (ANC below 500) — especially in patients on chemotherapy — is a medical emergency because even minor infections can become life-threatening without enough neutrophils to fight them.
Can stress raise my neutrophil count?
Yes. Physical stress (surgery, trauma, intense exercise) and even emotional stress can trigger the release of hormones like cortisol and epinephrine that cause a temporary spike in neutrophils. This is a normal physiological response and usually resolves within hours.
Are neutrophils the same as white blood cells?
No — neutrophils are one type of white blood cell. Your total WBC count includes neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Neutrophils are typically the most abundant, making up 40–70% of all white blood cells in healthy adults.