Which of the following correctly lists glycogen staining reactions?

• A. PAS (+), diastase (sensitive), Bauer-feulgen (+), Best carmine (+)
• B. PAS (-), diastase (resistant), Bauer-feulgen (-), Best carmine (-)
• C. PAS (+), diastase (resistant), Mallory’s trichrome (+), Alcian blue (+)
• D. PAS (+), diastase (sensitive), Mallory stain (+), Alcian blue (+)

Answer: (A)

Glycogen is a carbohydrate stored in cells, and its histochemical detection relies on stains that react with polysaccharides. The key feature is that glycogen gives a positive PAS reaction, but this signal is lost when the tissue is treated with diastase because the glycogen is digested. That diastase sensitivity is what differentiates glycogen from other diastase-resistant carbohydrates that can also stain with PAS.

So a correct glycogen staining pattern includes PAS positivity and diastase sensitivity. In addition, glycogen can be demonstrated by other carbohydrate-specific stains such as Best carmine and Bauer–Feulgen, which will also yield positive results for glycogen-containing structures. This combination aligns with the known behavior of glycogen in histochemical testing: a PAS-positive, diastase-sensitive profile, with supportive positive results on glycogen-targeting carbohydrate stains like Best carmine and Bauer–Feulgen.

The other options fail because they either omit PAS positivity, show diastase resistance, or include stains (like Mallory’s or Alcian blue) that do not indicate glycogen.