Alcian Blue pH 1.0 and pH 2.5 both demonstrate glycogen.

• A. True
• B. False
• C. Only pH 1.0 demonstrates glycogen
• D. Only pH 2.5 demonstrates glycogen

Answer: (B)

Alcian Blue works by binding to acidic polysaccharides, with its access depending on the pH to distinguish sulfated from carboxylated mucopolysaccharides. Glycogen, however, is a neutral polymer and lacks those acidic groups, so Alcian Blue does not stain glycogen at either pH 1.0 or pH 2.5. In histology, glycogen is detected with PAS (often after diastase digestion to differentiate from mucins), not with Alcian Blue. Therefore the statement that both pH levels demonstrate glycogen is not correct.