What ANC defines severe agranulocytosis?

• A. ANC < 0.5-1.0 x10^9
• B. ANC < 0.2-0.5 x10^9
• C. ANC < 1.5 x10^9
• D. ANC < 2.0 x10^9

Answer: (B)

Absolute neutrophil count (ANC) is the blood test used to gauge neutropenia and infection risk. Severe agranulocytosis is defined by a very low ANC, typically in the range of about 0.2 to 0.5 x10^9/L (200–500 cells per microliter). Counts in this range reflect profound depletion of neutrophils, leaving patients highly vulnerable to bacterial infections. Normal ANC is roughly 2.0–7.0 x10^9/L, so dropping into 0.2–0.5 x10^9/L represents a severe level of neutropenia and is the threshold used to classify severe agranulocytosis. Clinically, this level prompts urgent actions such as reviewing patient medications, monitoring closely for infections, and considering supportive therapies as needed.