Which condition tends to have more mature neutrophils on differential?

• A. Leukemoid reaction
• B. CML
• C. Both show similar maturation
• D. Neither condition shows mature neutrophils

Answer: (A)

The essential idea is that a reactive, non-neoplastic process drives neutrophilia with predominantly mature neutrophils on the smear. In a leukemoid reaction, the rise in white cells comes from mature and nearly-mature neutrophils with a left shift (more band forms), reflecting a reactive response to infection or stress. In contrast, chronic myeloid leukemia involves clonal expansion of myeloid cells with arrest of maturation, so the differential shows a broad spectrum of immature granulocytes (myelocytes, metamyelocytes, etc.), not mainly mature neutrophils. Therefore, more mature neutrophils on the differential point toward a leukemoid reaction.