Neutrophil analysis causes results and importance of the test

The neutrophil count test is a simple but very important blood test, as it reflects the strength of the immune system and the body's ability to fight infections. Through this test, the doctor can determine the percentage of neutrophils in the blood, whether it is normal, elevated, or low, and what it indicates regarding diseases, bacterial or viral infections, or issues with bone marrow. In this article, we will explore in detail the importance of the neutrophil count test, how it is conducted, how to interpret its results, the causes of elevated or low levels, and tips for maintaining normal neutrophil levels.

What is the Neutrophil Count Test?

The neutrophil count test is a part of the complete blood count (CBC with differential), and it measures the number and percentage of neutrophils in the blood. Neutrophils are a type of white blood cell responsible for fighting bacterial and fungal infections. Therefore, this test is very important for evaluating the strength of the immune system.

Why does a doctor request a neutrophil count test?

Doctors typically request this test for important reasons such as:

Diagnosing bacterial or viral infections.
Evaluating the strength of the immune system.
Monitoring chemotherapy or antibiotic treatments.
Diagnosing or monitoring blood diseases or bone marrow issues.

What are the normal values for neutrophils?

Percentage of neutrophils: 40% – 60% of white blood cells.
Absolute neutrophil count (ANC): 1500 – 8000 cells/µL of blood.

What does an elevated neutrophil count mean?

An elevated neutrophil count often indicates:

Acute bacterial infections.
Severe or chronic infections.
Severe stress or post-surgical recovery.
Some medications like corticosteroids or bone marrow-stimulating drugs.

What does a low neutrophil count mean?

A low neutrophil count often points to:

Viral infections.
Bone marrow problems or blood disorders.
Some medications like chemotherapy.
Deficiencies in vitamins and minerals such as B12 or folic acid.

Does the test require fasting?

Typically, fasting is not required for this test. However, it's recommended to be in a calm state and not fatigued before blood is drawn to ensure accurate results.

Is the blood draw painful?

The blood is drawn from a vein using a small needle. The pain is minimal and disappears once the procedure is completed. You might experience a slight bruise or redness at the needle site, but it will fade within a few days.

Can medications affect the results of the test?

Yes, some medications can affect neutrophil levels:

Increase neutrophils: Corticosteroids, bone marrow-stimulating drugs.
Decrease neutrophils: Chemotherapy, immunosuppressive drugs, certain antibiotics.

When should the test be repeated?

If the results are abnormal or don’t match the symptoms.
After treating an infection or adjusting medications to track changes.

Are elevated or decreased neutrophil counts permanent?

Changes are typically temporary and depend on the underlying cause. If the change persists for a long period, medical follow-up and additional tests are necessary.

The difference between mature and immature neutrophils

Mature neutrophils (Segs): Fully developed white blood cells that are very effective at fighting bacteria.
Immature neutrophils (Bands): New cells that haven’t fully matured, often increased during acute infections.

What is the Absolute Neutrophil Count (ANC) and why is it important?

ANC = the actual number of neutrophils per microliter of blood.
It is critical for assessing infection risk, especially in patients with weakened immune systems or neutropenia.

Do neutrophil levels change during pregnancy?

Yes, during normal pregnancy, neutrophil levels may slightly increase due to hormonal changes. This increase is usually temporary and does not indicate a health problem.

Can children undergo the same test?

Yes, neutrophil testing can be done on children and infants. Normal values may vary slightly depending on age, but the purpose remains the same: evaluating immunity and monitoring infections.

Can diet affect neutrophil levels?

Yes, deficiencies in certain vitamins and minerals, such as:

B12
Folic acid
Copper

...can lead to decreased neutrophils. A balanced diet helps maintain normal neutrophil levels.

Are neutrophils alone sufficient for diagnosing a disease?

No, neutrophils are part of the complete blood count (CBC). Doctors always interpret them alongside other white blood cell counts, symptoms, and additional tests to reach an accurate diagnosis.

How often should the neutrophil count test be done?

Immune-compromised patients or those undergoing chemotherapy: Regular weekly monitoring or as per the doctor’s instructions.
In the case of infections or inflammation: As needed to assess the body’s response.

Do neutrophil levels change due to psychological or physical stress?

Yes, extreme stress or intense physical activity can temporarily elevate neutrophil levels. After rest, levels usually return to normal.

Can neutrophils indicate the type of infection?

Generally speaking:

Elevated neutrophils often indicate bacterial infections.
Decreased neutrophils usually point to viral infections.

However, a final diagnosis requires additional tests and a full medical evaluation.

Is the neutrophil test part of a routine examination?

Yes, neutrophil testing is often done as part of a complete blood count (CBC), which is a routine health checkup or when symptoms are present.

Types of Neutrophil Tests

Neutrophil Test within Complete Blood Count (CBC with differential)
This is the most common neutrophil test. It analyzes all white blood cells, including neutrophils, and provides:
- Percentage of neutrophils (Neutrophil %)
- Absolute Neutrophil Count (ANC)
It is used for diagnosing infections, assessing immunity, and monitoring blood disorders.
Absolute Neutrophil Count (ANC)
This focuses on the actual number of neutrophils in microliters of blood. It’s more accurate than the percentage in assessing infection risk, especially in:
- Chemotherapy patients.
- Those with bone marrow diseases or weakened immunity.
Mature vs. Immature Neutrophils (Segs vs. Bands)
Neutrophils are sometimes divided into:
- Segs (Segmented neutrophils): Mature neutrophils, most effective at fighting infections.
- Bands (Immature neutrophils): New neutrophils that are often elevated during acute infections.
This classification helps doctors differentiate between acute and chronic infections.
Special Neutrophil Tests
Additional tests may be performed to evaluate neutrophil functions, such as:
- Phagocytosis Test
- Oxidative Burst Test
These are typically used when there’s suspicion of inherited or acquired immunodeficiency diseases.

Indications for Neutrophil Testing

Neutrophil testing is requested for various purposes to assess the body’s health and immune function, including:

Infection Diagnosis
- Acute bacterial infections: Elevated neutrophils often indicate active bacterial infections, such as strep throat, pneumonia, or urinary tract infections.
- Viral infections: Decreased neutrophils can point to viral infections like the flu or coronavirus.
Treatment Monitoring
- Antibiotics or infection treatments: Helps doctors assess the effectiveness of treatment and recovery.
- Chemotherapy or immunosuppressive drugs: Some medications lower neutrophils, so regular monitoring is crucial to avoid serious infections.
Assessing Immunity
A low neutrophil count (neutropenia) indicates weakened immunity and an increased risk of infections, especially in those with immune disorders or blood-related conditions.
Blood and Bone Marrow Diseases Diagnosis
Bone marrow diseases like anemia or leukemia affect neutrophil production. The test is part of a comprehensive assessment of white blood cell functions and immunity.
Chronic Inflammation Monitoring
Chronic diseases like rheumatoid arthritis or lupus may affect neutrophils. Tracking neutrophil counts helps doctors assess disease activity and its impact on immunity.
Emergency or Hospitalization Cases
In cases of unexplained fever, severe infection, or post-surgery, the test helps determine if the body is dealing with a serious infection.

Steps for Neutrophil Count Test

Preparation Before the Test
Inform your doctor about any medications or supplements you are taking, as they may affect the blood results. Avoid extreme stress or intense physical activity before the test to prevent a temporary rise in neutrophils. The test generally does not require fasting, but being calm and not fatigued is recommended. Notify the doctor if you have current infections or chronic diseases like blood disorders.
Preparing the Blood Draw Site
A clean, sterile site will be prepared at the lab or hospital. The skin will be disinfected with alcohol to prevent contamination, and the nurse or technician will wear sterile gloves.
Blood Sample Collection
A small needle will be used to draw blood from the vein. Usually, 2–5 mL of blood is collected in a tube containing an anticoagulant (EDTA). You may be asked to stay still to ease the procedure.
Processing the Sample in the Lab
After collection, the blood sample is gently mixed with the anticoagulant and sent to modern blood analyzers.
Laboratory Testing
The full blood count (CBC) is analyzed to determine the percentages of white blood cells, including neutrophils. In some labs, the absolute neutrophil count (ANC) is calculated, which is crucial for evaluating infection risk.

Neutrophil Count Test Results

1️⃣ Normal Neutrophil Values

Neutrophil percentage: 40% – 60% of white blood cells.
Absolute Neutrophil Count (ANC):
- Normal: 1500 – 8000 cells/µL of blood
- Mild decrease: 1000 – 1500 cells/µL
- Severe decrease: <1000 cells/µL → High risk of infection

2️⃣ Interpreting Results Based on Neutrophil Changes

Result	Possible Medical Meaning	Notes
Increased neutrophils (Neutrophilia)	Acute bacterial infection, severe inflammation, stress or shock, some types of cancer	Usually temporary, returns to normal after treatment or resolution of cause
Decreased neutrophils (Neutropenia)	Viral infection, bone marrow problems, medications like chemotherapy, autoimmune diseases	Severe decrease increases infection risk and requires careful monitoring
Slight increase	Postpartum, smoking, psychological stress	Usually temporary and does not require treatment
Moderate decrease	Vitamin deficiencies, chronic infection, medication effects	Monitoring and additional tests needed to determine the cause

3️⃣ Absolute Neutrophil Count (ANC) and Its Importance

ANC > 1500: Normal, strong immunity
ANC 1000–1500: Mild decrease, caution advised
ANC 500–1000: Moderate decrease, moderate infection risk
ANC < 500: Severe decrease, high infection risk, urgent follow-up needed

4️⃣ Important Notes

Results are always interpreted in conjunction with clinical symptoms.
Sometimes changes are temporary, such as after stress or a mild infection.
A doctor may request a repeat test or additional tests if results don’t match the clinical condition.

Causes of Elevated Neutrophils (Neutrophilia)

1️⃣ Bacterial Infections

The most common cause of neutrophilia.
Neutrophils increase to fight bacteria.
Examples: bacterial throat infection, pneumonia, urinary tract infections, infected wounds.

2️⃣ Acute or Chronic Inflammation

Acute: appendicitis, skin infections
Chronic: rheumatoid arthritis, some inflammatory bowel diseases

3️⃣ Stress or Shock

Severe physical or psychological stress can temporarily elevate neutrophils.
Examples: surgery, burns, major injuries

4️⃣ Smoking or Certain Medications

Chronic smoking can increase neutrophils.
Some medications like corticosteroids or bone marrow-stimulating drugs cause temporary increases.

5️⃣ Blood Disorders or Cancer

Blood cancers such as leukemia can cause abnormally high neutrophils.
Bone marrow tumors and some cancers can also increase neutrophils.

6️⃣ Pregnancy or Postpartum

During pregnancy or immediately after childbirth, neutrophil levels may naturally rise.
Usually temporary and returns to normal shortly.

Risks Associated with Neutrophil Count Test

A. General Risks of Blood Draw

Bruising or minor bleeding: May appear at the needle site; usually resolves in a few days. Applying pressure immediately reduces bruising.
Pain or sensitivity: Mild stinging occurs during needle insertion, disappears afterward.
Dizziness or fainting: Some people feel lightheaded, especially with fear of needles or long fasting. Sit or lie down during the procedure and drink water afterward.
Rare infection: Extremely rare due to sterile procedures.
Special cases:
- People with bleeding disorders (e.g., low platelets) have higher bleeding risk.
- Severely immunocompromised patients need extra caution to prevent contamination.

B. Risks Related to Test Results

Inaccurate results may lead to incorrect diagnosis or treatment.
To prevent this:
- Follow test instructions carefully.
- Inform the doctor of all medications and conditions.
- Repeat testing if results do not match clinical signs.

C. Tips to Reduce Risks

Sit calmly and avoid moving the arm during blood draw.
Apply pressure after the draw to reduce bruising.
Drink water after the test to prevent dizziness.
Inform the doctor about bleeding or immune problems before the test.
Ensure lab tools are clean and sterile.

Causes of Decreased Neutrophils (Neutropenia)

1️⃣ Viral Infections

Some viral infections temporarily reduce neutrophils.
Examples: flu, COVID-19, measles, chickenpox.
Reason: neutrophils are used to fight viruses, or bone marrow temporarily produces fewer.

2️⃣ Bone Marrow Problems

Bone marrow produces blood cells.
Disorders can cause neutropenia, such as:
- Aplastic anemia
- Leukemia
- Bone marrow tumors or chronic diseases affecting production

3️⃣ Medications and Chemotherapy

Some drugs reduce neutrophil production:
- Cancer chemotherapy
- Immunosuppressants (corticosteroids, transplant drugs)
- Certain antibiotics or anti-inflammatory drugs

4️⃣ Immune Disorders

Autoimmune diseases may attack neutrophils.
Examples: lupus, other autoimmune conditions

5️⃣ Vitamin or Mineral Deficiency

Deficiency in nutrients affects neutrophil production:
- Vitamin B12
- Folic acid
- Copper

6️⃣ Rare Genetic Conditions

Some people are born with neutrophil production disorders, such as:
- Congenital neutropenia
- Cyclic neutropenia (periodic neutrophil decrease)

Medications That Affect Neutrophil Results

1️⃣ Drugs That Increase Neutrophils (Neutrophilia)

Drug	Effect on Neutrophils	Notes
Corticosteroids (e.g., Prednisone)	Temporarily increases neutrophils	Common after high or long-term doses
Bone marrow stimulants (e.g., G-CSF)	Increases neutrophil production	Used for chemotherapy patients
Stress or shock medications	Temporary increase	Sometimes after surgery or severe injury

2️⃣ Drugs That Decrease Neutrophils (Neutropenia)

Drug	Effect on Neutrophils	Notes
Chemotherapy	Significantly decreases neutrophils	Requires careful monitoring to prevent infection
Some antibiotics (e.g., Chloramphenicol)	May reduce neutrophils	Rare but known
Immunosuppressants (e.g., Cyclosporine, Methotrexate)	Reduces neutrophil production	Used for autoimmune diseases or transplants
Anti-epileptics or some thyroid drugs	Sometimes reduce neutrophils	Varies by individual and dose

3️⃣ Other Drugs with Temporary Effects

Some stimulants or stress medications may temporarily raise neutrophils.
Vitamins or supplements usually don’t affect neutrophils, but B12 or folic acid deficiency can lower them.

Important Tips Before the Test

Inform your doctor about all medications and supplements.
If the test is done after taking a drug known to alter neutrophils, your doctor may request a repeat test later.
Some drugs cause temporary changes, which are usually not concerning unless significant or persistent.

Tips to Maintain Normal Neutrophil Levels

1️⃣ Proper Nutrition

Increase proteins: Meat, fish, eggs, legumes are important for blood cell production.
Vitamins and minerals:
- B12: meat, fish, eggs, milk
- Folic acid: leafy greens, lentils, beans
- Copper & Zinc: nuts, whole grains, meat
Fruits and vegetables: Contain antioxidants that support immunity and blood cell health

2️⃣ Healthy Lifestyle

Adequate sleep: 7–8 hours/day helps white blood cell production
Moderate exercise: walking or swimming 30 minutes/day strengthens immunity
Avoid chronic stress: psychological stress can temporarily affect neutrophils

3️⃣ Avoid Harmful Factors

Quit smoking: chronic smoking can increase or impair neutrophils
Limit alcohol: excessive drinking reduces immune efficiency

4️⃣ Infection Prevention

Wash hands regularly, especially before eating and after using the bathroom
Avoid close contact with sick individuals if immunocompromised or neutropenic
Recommended vaccines (flu, pneumonia) prevent infections affecting neutrophils

5️⃣ Monitor Medications

Some medications reduce neutrophils (e.g., chemotherapy, immunosuppressants)
Regular neutrophil monitoring is necessary
Do not stop any medication without consulting your doctor

6️⃣ Regular Tests

CBC tests regularly if chronic conditions or medications affect neutrophils
Monitoring allows early detection of abnormal neutrophil levels and timely action

Treatment of Elevated Neutrophils (Neutrophilia) with Medications
Elevated neutrophils usually indicate an underlying cause, not a disease itself. Treatment targets the cause:

A. Treating Bacterial Infections

Antibiotics are the main treatment: e.g., amoxicillin, cephalosporins, or others depending on infection type
Neutrophil levels usually return to normal after controlling the infection

B. Treating Chronic Inflammation

Anti-inflammatory or immunosuppressive medications based on the disease:
- Rheumatoid arthritis: Methotrexate, Sulfasalazine
- Lupus: corticosteroids or immunosuppressive drugs
Goal: reduce inflammation and restore neutrophil levels

C. Drugs to Reduce Neutrophils (Rare Cases)

Rarely, if neutrophils are very high without clear cause, Hydroxyurea may be used to reduce production in specific cases

Treatment of Low Neutrophils (Neutropenia) with Medications
Low neutrophils are more serious due to increased infection risk. Treatment depends on the cause:

A. Bone Marrow-Stimulating Drugs

G-CSF (Granulocyte Colony Stimulating Factor), e.g., Filgrastim, Pegfilgrastim
Given in severe neutropenia, especially post-chemotherapy, to stimulate neutrophil production

B. Adjust or Stop Causative Medications

If neutropenia is caused by a drug (chemotherapy, immunosuppressants, some antibiotics), the dose may be adjusted or replaced under medical supervision

C. Preventive Anti-Infection Medications