Agranulocytosis is a potential adverse effect associated with some antipsychotics, notably clozapine. Which option correctly identifies its laboratory finding?

• A. Hyperkalemia
• B. Agranulocytosis
• C. Hyponatremia
• D. Hyperglycemia

Answer: (B)

Agranulocytosis means a dangerous drop in neutrophils, the white blood cells that fight infection. Clozapine carries this risk, so the lab finding you’d look for is a severely reduced absolute neutrophil count on a complete blood count. This directly matches the adverse effect associated with this drug. The other lab abnormalities listed (hyperkalemia, hyponatremia, hyperglycemia) are not the characteristic hematologic finding of agranulocytosis and thus aren’t the correct lab marker for this issue. In clinical practice, neutropenia from clozapine requires regular ANC monitoring because infection risk rises as neutrophil counts fall.