What is the process of selectively removing excess or non-specific stain from tissue components called?

• A. Differentiation
• B. Destaining
• C. Dehydration
• D. Clearing

Answer: (A)

Differentiation is the step that selectively removes excess stain to sharpen contrast between tissue components. After staining, some areas bind stain more weakly or non-specifically; a controlled differentiating treatment washes away this loosely bound dye, making the strongly stained structures stand out more clearly under the microscope. This precise removal helps reveal true boundaries and improves visualization of details. The differentiating step is performed with a differentiating solution (often a brief acidified solvent) and must be timed carefully to avoid over- or under-decolorization. Destaining, in contrast, refers to removing stain after staining to decolorize or prepare for another stain, while dehydration and clearing are different tissue processing steps unrelated to selectively removing excess stain.