Which statement about Romanowsky stains is true?

• A. They never include Giemsa.
• B. They include Giemsa as an example.
• C. They are used to measure blood sugar.
• D. They stain only bacteria.

Answer: (B)

Romanowsky stains are a family of polychrome stains used to differentiate cellular components in blood and bone marrow smears by combining basic and acidic dyes. They produce distinct colors that highlight nuclei, cytoplasm, and granules, making it possible to identify different blood cells and detect parasites.

Giemsa is a classic example within this stain family, formulated with azure dyes and eosin to yield characteristic color patterns (blue-purple nuclei and pink to pinkish cytoplasm). That’s why including Giemsa as an example is the correct statement.

These stains aren’t used to measure blood sugar—such an analysis is a chemical assay, not a staining technique. They also aren’t limited to staining bacteria; their primary purpose is staining blood cells and related structures (and can reveal intracellular organisms like parasites), not exclusively bacteria.