Neutropenia Definition and Classification
Neutropenia is defined as an absolute neutrophil count (ANC) of less than 1,500 cells/μL. 1
The severity of neutropenia is classified as follows:
| Grade | Neutrophil Count |
|---|---|
| 0 | ≥2,000 cells/μL |
| 1 | 1,500-2,000 cells/μL |
| 2 | 1,000-1,500 cells/μL |
| 3 | 500-1,000 cells/μL |
| 4 | <500 cells/μL |
Severity Categories
Neutropenia is typically categorized by severity:
- Mild neutropenia: ANC between 1,000-1,500 cells/μL
- Moderate neutropenia: ANC between 500-1,000 cells/μL
- Severe neutropenia: ANC less than 500 cells/μL 1
- Profound neutropenia: ANC less than 100 cells/μL 1
Clinical Implications
The clinical significance of neutropenia correlates with its severity:
- Severe neutropenia (ANC < 500 cells/μL) significantly increases the risk of infectious complications, particularly after invasive procedures 1
- Patients with ANC < 500 cells/μL require special consideration for medical procedures and may need prophylactic antibiotics 1
- Febrile neutropenia (temperature ≥38.3°C or ≥38.0°C sustained over 1 hour with neutropenia) is a medical emergency requiring immediate antibiotic therapy 1
Management Considerations
For patients with severe neutropenia:
- Elective invasive procedures should be avoided when ANC < 500 cells/μL 1
- G-CSF therapy may be indicated for severe neutropenia with standard dosing of 5 μg/kg/day subcutaneously until ANC recovery 1
- Close monitoring is essential for early detection of infectious complications 1
Common Pitfalls
- Failing to recognize that neutropenia definitions may vary slightly between different clinical contexts
- Not appreciating that the risk of infection increases dramatically when ANC falls below 500 cells/μL
- Overlooking the need for immediate intervention in cases of febrile neutropenia, which represents a medical emergency
Neutropenia assessment should always be interpreted in clinical context, as the implications and management differ based on whether it is acute or chronic, and whether it is related to underlying hematologic disorders, medication effects, or other causes.