What value defines severe neutropenia?

• A. <100
• B. <500
• C. <1000
• D. <2000

Answer: (B)

Neutropenia severity is based on the absolute neutrophil count (ANC), which shows how many neutrophils are available to fight infection. Normal ANC is roughly 1500–8000 cells per microliter. As the ANC drops, infection risk rises. Severe neutropenia is defined as an ANC below 500 cells per microliter, indicating a high risk for serious bacterial and fungal infections. When ANC falls under 500, clinicians treat this as a high-priority situation, often implementing neutropenic precautions and considering prompt antibiotic therapy if fever or infection signs appear. Understanding these thresholds helps explain why the body becomes far more vulnerable as neutrophil counts plummet, and why <500 is the cutoff used to label severe neutropenia.