Which white blood cell is identified by rod-shaped granules in the cytoplasm?

• A. Lymphocyte
• B. Monocyte
• C. Eosinophil
• D. Neutrophil

Answer: (C)

Recognizing white blood cells by cytoplasmic granule appearance is the key idea here. Eosinophils stand out because their cytoplasm is packed with large, eosin-staining granules that often look rod- or crystalline-shaped under standard stains. This rod-shaped granule pattern is a classic marker for eosinophils on a smear, making them identifiable despite other cells having different granule content or none at all. Neutrophils have small, neutral granules and a multilobed nucleus; basophils show many dark, intensely staining granules that mask the nucleus; lymphocytes have minimal cytoplasm and few or no visible granules; monocytes may have some azurophilic granules but not rod-shaped. So the cell with rod-shaped cytoplasmic granules is the eosinophil.