In which situations are cytology samples briefly heated with a flame or hair dryer?

Cytology samples are briefly heated with a flame or hair dryer primarily for Gram's stain and to dissolve excess ear wax during the preparation process. The application of heat helps to fix the cells to the slide, making them adhere better and allowing for a more effective staining process. In the context of a Gram stain, heating helps to preserve the cellular structure and enhances the visibility of the bacteria by ensuring uniform staining and clarity under a microscope.

When it comes to dissolving excess ear wax, heating can aid in liquefying the wax, making it easier to prepare samples for examination. This is particularly useful in otic cytology, where clear samples are essential for accurate diagnosis.

The other contexts presented in the options do not typically require such methods; for instance, blood tests, skin lesion biopsies, and bacterial culture preparation follow different procedures that do not involve heating cytology samples in this way.