American Society for Clinical Pathology (ASCP) Histotechnologist Practice Test

What type of staining method is needed to reveal glycogen in tissue sections?

1. Silver stain

2. Hematoxylin and Eosin

3. Periodic acid-Schiff stain

4. Fischer's stain

The correct answer is: Periodic acid-Schiff stain

The correct choice is the Periodic acid-Schiff (PAS) stain, which is specifically used to detect glycogen in tissue sections. This staining method relies on the oxidation of glycogen by periodic acid, which results in the formation of aldehyde groups. These aldehydes then react with the Schiff reagent, producing a magenta or pink coloration where glycogen is present. This method is highly selective for polysaccharides like glycogen and is commonly employed in histopathology to highlight glycogen storage diseases or in studies of metabolic function within tissues. The specific reaction of the PAS stain provides a clear and reliable visualization of glycogen, making it a preferred choice amongst various staining techniques for this purpose. Other staining methods, such as silver stains and hematoxylin and eosin, do not specifically target glycogen, focusing instead on different cellular components or structures. Fischer's stain is tailored for specific applications but does not provide the specificity needed for glycogen detection like the PAS stain does.