Hematoxylin and Eosin Staining Flashcards

What does 'over-differentiation' of hematoxylin produce in an H&E section?

Answer: Pale or unstained nuclei

Over-differentiation removes too much hematoxylin, resulting in pale or ghost nuclei that are difficult to visualize.

What type of hematoxylin is most commonly used in routine histology laboratories in the US?

Answer: Harris hematoxylin

Harris hematoxylin is the most widely used progressive/regressive hematoxylin in US histology labs for routine H&E staining.

Which method of hematoxylin staining requires a differentiation step?

Answer: Regressive staining

Regressive staining over-stains tissue and then differentiates to remove excess dye from non-target sites, requiring a controlled acid-alcohol step.

What is a common cause of eosin staining appearing too pale in H&E sections?

Answer: Insufficient eosin concentration or exhausted eosin solution

Diluted or exhausted eosin solution lacks sufficient dye concentration to adequately stain cytoplasmic proteins.

Which reagent is used to mount coverslips on H&E sections stained using an alcohol-based final dehydration?

Answer: Xylene-based mounting medium (e.g., Permount)

Xylene-based mounting media like Permount are miscible with the dehydrated, xylene-cleared sections and provide permanent, clear mounts.

What staining result indicates that sections were not completely deparaffinized before H&E staining?

Answer: Unstained or poorly stained areas with paraffin residue

Residual paraffin acts as a barrier to aqueous dyes, producing unstained patches or areas with poor dye penetration.