Which staining method uses a fluorescence dye to detect fungal elements?

• A. Gram
• B. Grocott
• C. Auramine-rhodamine
• D. PAS

Answer: (C)

Fluorescence staining uses dyes that emit light when excited by a specific wavelength, so the specimen must be examined with a fluorescence microscope to see the elements labeled by the dye. Among these options, the stain that uses a fluorescence dye is auramine-rhodamine, which produces bright fluorescence under the microscope and is used to visualize targeted elements with that illumination method. The other stains are read with standard light microscopy and do not rely on fluorescence: Gram stain uses crystal violet and a counterstain; Grocott-Gomori methenamine silver is a silver stain seen in brightfield; PAS relies on color change in brightfield as well. In labs, a dedicated fungal fluorescence stain like calcofluor white is common, but from the given choices, auramine-rhodamine is the one that uses a fluorescence dye.