Absolute Neutrophil Count (ANC)
Calculates absolute neutrophil count to assess neutropenia severity
Calculator
Why use it
Essential for identifying and grading neutropenia in chemotherapy patients. Determines eligibility for chemotherapy, infection risk, and the need for prophylactic antibiotics or G-CSF. Guides decisions about hospital admission for febrile neutropenia.
About
The Absolute Neutrophil Count (ANC) measures the actual number of neutrophils in the blood by multiplying the total white blood cell count by the percentage of neutrophils (segs + bands). ANC is the key laboratory value for assessing neutropenia severity, which is a critical complication of chemotherapy and bone marrow failure states.
When to use
- After chemotherapy to assess nadir counts
- Febrile neutropenia evaluation
- Monitoring patients with bone marrow failure (aplastic anemia, MDS)
- Pre-chemotherapy assessment for dose modifications
- Evaluating risk for invasive bacterial or fungal infection
Formula
Pearls & pitfalls
- Febrile neutropenia: ANC < 500 cells/µL (or < 1,000 expected to fall below 500) with fever ≥ 38.3°C or sustained ≥ 38.0°C for 1 hour.
- Bands (immature neutrophils) are counted in addition to segmented neutrophils because they retain microbicidal function.
- ANC nadir typically occurs 7–10 days after chemotherapy, depending on the regimen.
- G-CSF (filgrastim, pegfilgrastim) may be indicated for ANC < 500 or high-risk chemotherapy regimens.
- MASCC score should be calculated in patients with febrile neutropenia to stratify for outpatient vs. inpatient treatment.
- Chronic benign neutropenia in African populations: ANC may be lower at baseline without increased infection risk.
Next steps
ANC ≥ 2,000: Normal. ANC 1,000–1,999: Mild neutropenia — monitor. ANC 500–999: Moderate neutropenia — increased infection risk; consider prophylaxis. ANC < 500: Severe neutropenia — high risk; fever requires immediate evaluation and empiric antibiotics. ANC < 100: Profound neutropenia — life-threatening; consider G-CSF.
Evidence
Standard laboratory measurement validated in hundreds of oncology clinical trials. ASCO and IDSA febrile neutropenia guidelines use ANC < 500 as the threshold for high-risk categorization.