PAS & PASD Flashcards
What type of stain is PAS?
A carbohydrate stain
What is the target tissue component of PAS?
Group 1 CHO (neutral polysaccharides)
What staining principle does PAS use?
Histochemical
What are the positive controls used for PAS?
Liver, kidney, muscle
What kind of stain is this: A colorless compound reacts with a dialdehyde in tissue to form a colored end product
Histochemical stain
What are the counterstain options when using PAS?
Hematoxylin (regressive stain)
Alcian blue
If the pathologist is looking specifically for glycogen, what confirmatory test is ordered?
PAS Diastase (PASD)
What is the principle of PASD?
Diastase will digest polysaccharides into monosaccharides, which are water soluble
The PASD procedure is performed the same as PAS except what?
The digestion step is added and done first
What tissue is typically used to QC glycogen for PASD?
Liver
What kinds of cells in the liver are PASD resistant?
Kupffer Cells
What property should the fixative used for PASD have?
Should preserve glycogen
What will happen if you use old/incorrectly stored Schiff’s reagent for PASD?
It will give false negative results
Why shouldn’t you use the Schiff reagent if it has turned pink?
Because it has become unreduced and will not impart colour to the target tissue component
What are the staining results of PAS on tissue components?
Nuclei are blue
Glycogen is magenta
Other PAS + components are magenta
What is a cheaper version of diastase?
Saliva
