From the Guidelines
The neutropenia cutoff value is typically considered to be below 500 cells/mm³, as this is the threshold at which the risk of infection increases significantly and clinical decision-making regarding prophylactic antibiotics and other interventions is often guided. According to the most recent and highest quality study, 1, antibiotic prophylaxis should be started with the onset of neutropenia and continued until the ANC is >500/mm3, highlighting the importance of this cutoff value in clinical practice.
Definition and Severity of Neutropenia
Neutropenia is typically defined as an absolute neutrophil count (ANC) below 1,500 cells/mm³, though the severity is categorized based on specific cutoff values. Mild neutropenia ranges from 1,000-1,500 cells/mm³, moderate neutropenia from 500-1,000 cells/mm³, and severe neutropenia below 500 cells/mm³.
Clinical Decision-Making
The risk of infection increases significantly when the ANC falls below 500 cells/mm³, with the greatest risk occurring below 100 cells/mm³, which is considered profound neutropenia. These cutoffs guide clinical decision-making, including when to initiate prophylactic antibiotics, growth factors like filgrastim (G-CSF), or hospitalization. For chemotherapy patients, dose modifications are often recommended when ANC falls below 1,000 cells/mm³, with treatment delays typically occurring at levels below 500 cells/mm³, as supported by earlier guidelines 1.
Institution and Context Variability
It's essential to note that these thresholds may vary slightly between institutions and clinical contexts, and that neutropenia assessment should consider not just the absolute value but also the rate of decline, expected duration, and patient-specific risk factors for infection. However, the cutoff of 500 cells/mm³ remains a critical benchmark for guiding clinical decisions, as emphasized in the latest expert consensus guidelines 1.
Key Points for Clinical Practice
- Neutropenia is defined as an ANC below 1,500 cells/mm³.
- The severity of neutropenia is categorized based on specific cutoff values.
- Clinical decision-making is guided by the ANC cutoff value, particularly the threshold of 500 cells/mm³.
- Prophylactic antibiotics and other interventions are often initiated based on this cutoff value.
- Institution and context variability should be considered, but the 500 cells/mm³ threshold remains a critical benchmark.
From the FDA Drug Label
The main efficacy endpoint was duration of severe neutropenia ANC < 500/mm3 ANC response from baseline (< 500/mm3) A statistically significant reduction in the median number of days of severe neutropenia (ANC < 500/mm3) time to recovery of ANC to ≥ 500/mm3
The neutropenia (absolute neutrophil count (ANC) deficiency) cutoff value is ANC < 500/mm3 2.
From the Research
Neutropenia Cutoff Value
The neutropenia cutoff value is defined as an absolute neutrophil count (ANC) less than 1.5 × 10(9)/l or 1500 cells/microL [ 3 , 4 , 5 , 6 , 7 ].