What component of the Romanowsky stain is red and what is its function?

The component of the Romanowsky stain that is red is eosin, and its primary function is to stain cytoplasmic features. Eosin is an acidic dye that interacts with the basic components of the cells, particularly proteins found in the cytoplasm. This staining allows for the visualization of various structures within the cytoplasm, such as organelles and other cellular components, which can be critical for identifying cellular morphology and diagnosing potential abnormalities.

Understanding the role of eosin in the context of the Romanowsky stain helps in cytological assessments. The combination of eosin and the blue dye (like methylene blue) provides contrast that highlights different elements within the cells, offering clearer insights into their health and function.