H&E stained slides of small intestine reveal muscle, collagen, and RBCs all stained the same shade of pink. This indicates:

• A. Poor differentiation of eosin
• B. Over-differentiation of hematoxylin
• C. Incomplete dehydration
• D. Excess water during staining

Answer: (A)

In H&E staining, eosin binds to eosinophilic structures like cytoplasm, muscle, collagen, and red cell contents, giving them a pink color, while hematoxylin stains nuclei blue. Proper differentiation of eosin ensures these eosinophilic elements don’t all look the same pink and you can distinguish between them. When muscle, collagen, and RBCs appear the same shade of pink, it means the eosin dye wasn’t differentiating properly, so these different structures are not contrasted as they should be. This is called poor differentiation of eosin.

Over-differentiation of hematoxylin would mainly dull nuclear staining and reduce contrast of basophilic components, not cause all eosinophilic structures to merge into one pink shade. Incomplete dehydration or excess water during staining tend to produce artifacts or overall poor staining quality rather than a specific loss of eosinophilic differentiation.