Unit Converter
Neutrophils (NEUT)
Synonyms
- NEUT%
- Neutrophil percentage
- Relative neutrophil count
- Neutrophil proportion
- Neutrophil fraction
- Polymorphonuclear cells (PMNs) - %
- Granulocyte percentage
Units of Measurement
- %
- Fraction (0–1 scale)
- Proportion of 1.0
Conversions
\text{Fraction} = \frac{\text{%}}{100} \text{%} = \text{Fraction} \times 100
Examples:
- 60% → 0.60
- 0.72 → 72%
Description
NEUT% represents the relative proportion of neutrophils (including band forms) in the white blood cell (WBC) differential.
While Absolute Neutrophil Count (ANC) represents the actual number of neutrophils per µL or liter,
NEUT% shows their proportional dominance among all leukocytes.
Changes in NEUT% reflect:
- Type of infection
- Immune response patterns
- Marrow activity
- Drug effects
- Stress responses
Physiological Role
Neutrophils are the primary innate immune cells, central to:
- Bacterial defense
- Fungal defense
- Inflammation
- Phagocytosis
- Reactive oxygen species generation
- NETosis (neutrophil extracellular traps)
They are the fastest responders in acute infection.
Clinical Significance
HIGH NEUT% (Neutrophilia - Relative)
May occur even if total ANC is normal - indicates relative dominance.
Causes
1. Acute Bacterial Infection (most common)
- Pneumonia
- Appendicitis
- Cellulitis
- Sepsis
2. Inflammation
- Rheumatoid arthritis
- Vasculitis
- IBD
3. Stress Reactions
- Surgery
- Trauma
- MI
- Exercise
- Seizures
4. Medications
- Corticosteroids
- Lithium
- G-CSF
5. Physiological Causes
- Pregnancy
- Smoking
6. Hematologic Conditions
- Myeloproliferative neoplasms
- Leukemoid reaction
- Early CML
NEUT% + Band Forms (Left Shift)
Indicates acute infection or severe inflammation.
LOW NEUT% (Relative Neutropenia)
May occur even when absolute neutrophil count is normal.
Causes
1. Viral Infections
Most common cause of low NEUT%.
2. Hypersplenism
3. Bone Marrow Suppression
- Chemotherapy
- Radiation
- Aplastic anemia
- Leukemia
4. Autoimmune Disorders
- SLE
- RA (Felty syndrome)
5. Nutritional Deficiencies
- B12 deficiency
- Folate deficiency
6. Drug Effects
Antipsychotics, antithyroid drugs, antibiotics (rare idiosyncratic reactions)
Reference Intervals
Adults
- 40 – 70%
(= 0.40–0.70 fraction)
Children
| Age | Reference Range |
| Newborn | 50–70% |
| 1–6 years | 20–55% |
| >6 years | 40–65% |
Children normally have lower NEUT% and higher lymphocyte %.
Patterns & Interpretation
High NEUT% + High ANC
→ Infection, inflammation, stress reaction, steroids
High NEUT% + Normal ANC
→ Relative neutrophilia (often due to lymphopenia or stress)
Low NEUT% + Low ANC
→ Neutropenia (drug-induced, marrow failure, severe infection)
Low NEUT% + Normal ANC
→ Relative neutropenia (lymphocytosis, early viral infection)
High NEUT% + Left shift
→ Strong indicator of bacterial infection
Diagnostic Uses
1. Infection Evaluation
- Bacterial infections → high NEUT%
- Viral infections → low NEUT%
2. Inflammatory Diseases
NEUT% increases with severe inflammation.
3. Stress & Endocrine Response
Acute stress → transient increases.
4. Hematologic Assessment
Helps detect myeloproliferative disorders.
5. Monitoring Therapy
- Steroids
- Chemotherapy
- G-CSF
6. Smear Correlation
NEUT% helps interpret:
- Toxic granulation
- Band forms
- Left shift
Analytical Notes
- Automated analyzers calculate NEUT% by differential WBC count
- Confirm abnormalities with peripheral smear
- Stress, smoking, and pregnancy alter NEUT%
- Bands may cause temporary elevation in NEUT%
Clinical Pearls
- NEUT% is useful but ANC is clinically more crucial for infection risk.
- High NEUT% without fever may reflect stress or steroid use.
- Viral infections → low NEUT% but elevated lymphocyte %.
- Left shift (bands) + high NEUT% → strong indicator of bacterial infection.
- Relative neutrophilia can occur even with a normal ANC.
Interesting Fact
Neutrophils release web-like structures known as NETs (Neutrophil Extracellular Traps) to trap and kill bacteria - discovered only in 2004.
References
- Tietz Clinical Chemistry & Molecular Diagnostics, 8th Edition - Hematology
- WHO Hematology Reference Standards
- Mayo Clinic Laboratories - Neutrophil Indices
- ARUP Consult - CBC Interpretation
- MedlinePlus / NIH - WBC Differential