Which statement best defines a leukemoid reaction in the context of infection or stress?

Which statement best defines a leukemoid reaction in the context of infection or stress?

• A. A malignant proliferation of white cells
• B. A reactive leukocytosis due to infection or stress
• C. A malignant increase in lymphocytes
• D. A reactive eosinophilia due to allergies

Answer: (B)

Leukemoid reaction is a dramatic, but reactive, rise in white blood cells in response to infection or physiologic stress. It is not a cancerous process; it reflects inflammation driving neutrophils to surge, often with a left shift showing immature neutrophils, while cells typically mature. A key clue is the high leukocyte count with preserved maturation and usually a high leukocyte alkaline phosphatase (LAP) score, which helps distinguish it from leukemia, where LAP is often low. The underlying trigger is infection, severe inflammation, or stress, sometimes from drugs or toxins. So this statement best defines a leukemoid reaction. The other descriptions point to malignant proliferations or to increases in other cell types (lymphocytes or eosinophils), which aren’t characteristic of a leukemoid response.

Leukemoid reaction is a dramatic, but reactive, rise in white blood cells in response to infection or physiologic stress. It is not a cancerous process; it reflects inflammation driving neutrophils to surge, often with a left shift showing immature neutrophils, while cells typically mature. A key clue is the high leukocyte count with preserved maturation and usually a high leukocyte alkaline phosphatase (LAP) score, which helps distinguish it from leukemia, where LAP is often low. The underlying trigger is infection, severe inflammation, or stress, sometimes from drugs or toxins. So this statement best defines a leukemoid reaction. The other descriptions point to malignant proliferations or to increases in other cell types (lymphocytes or eosinophils), which aren’t characteristic of a leukemoid response.