Definition
The ANC is the actual number of neutrophils (the white blood cells that fight bacterial & fungal infections) in the blood.
It is the key lab value used to assess bone marrow suppression after chemotherapy.
Formula
ANC is calculated from the CBC with differential:
ANC is calculated from the CBC with differential:
- WBC = white blood cell count (×10⁹/L)
- Neutrophils + Bands = percentage from differential
Example:
WBC = 2.0 ×10⁹/L, Neutrophils = 40%, Bands = 5%
ANC = 2.0 × (45/100) = 0.9 ×10⁹/L (900 cells/µL)
Clinical Categories (for oncology practice)
- Normal: > 2,000/µL
- Mild neutropenia: 1,000–1,500/µL
- Moderate neutropenia: 500–1,000/µL
- Severe neutropenia: < 500/µL → highest infection risk
- Profound neutropenia: < 100/µL
Oncology Relevance
- Most important predictor of infection risk during chemotherapy-induced myelosuppression.
- Guides chemotherapy dosing/cycle timing — treatment is often delayed or dose-reduced if ANC is too low.
- Key factor for febrile neutropenia:
- Defined as fever (≥38.3°C once or ≥38°C for >1h) + ANC < 500/µL (or expected to fall below 500).
- Requires urgent empiric broad-spectrum antibiotics.
- Supportive care:
- G-CSF (filgrastim, pegfilgrastim) used to shorten neutropenia and raise ANC.
- Patient counseling: avoid infection sources, report fever immediately.
In short:
ANC is the absolute neutrophil count, the most critical marker for infection risk in oncology patients receiving chemotherapy. It determines when to give chemo, when to hold, and when to start prophylaxis or urgent antibiotics.