Test Preparation : No special preparation required

Sample : Any Specimen/Slides

Methodlogy : Microscopy

Description :

WHAT IS IT?

Periodic acid-Schiff (PAS) staining is a technique for identifying mucosubstances such glycoproteins, glycolipids, and mucins as well as polysaccharides like glycogen in tissues. The vicinal diols in these sugars are oxidized by the periodic acid reaction, generally causing the bond between two nearby carbons that aren't entangled in the glycosidic linkage or ring closure in the ring of the monosaccharide units that are components of the stretched polysaccharides to break and creating a pair of aldehydes at the two free tips of each cracked monosaccharide ring. It is necessary to manage the oxidation situation properly to prevent further oxidation of the aldehydes. The Schiff reagent is then used to produce a purple-magenta hue from these aldehydes. As a counterstain, an appropriate basic stain is typically employed. Diastase, an enzyme that breaks down glycogen, is combined with PAS stain to create PAS diastase stain (PAS-D). Prior to the PAS stage, alcian blue is used in the Alcian Blue/Periodic Acid-Schiff (AB/PAS or AB-PAS) method.

WHY?

To focus on molecules (structures) with a high proportion of carbohydrate content, such as glycogen, glycoproteins, and proteoglycans frequently seen in connective tissue, glycocalyx, and basal laminae, PAS stain is frequently utilized. Staining with PAS can be used to help the diagnosis of a variety of medical disorders, including versus other storage disorders, glycogen storage disease, Adenocarcinoma that often releases mucus, Breast Paget's disease, soft portion of the alveolar sarcoma, Macrophage staining in Whipple's illness, Erythroleukemia and RBC immature leukemia and Fungal infection (magenta cell wall stain).

PRECAUTIONS

In histology and pathology, the Periodic Acid-Schiff (PAS) stain test is a critical technique for determining carbohydrates, notably glycogen and glycoproteins, inside tissue slices. The procedure entails acquiring and preserving the tissue sample, embedding it in paraffin wax, cutting thin sections, flattening and attaching them on glass slides, deparaffinizing them, treating them with periodic acid, coating them with Schiff reagent, and counterstaining them. After that, the slides are cleaned, dehydrated, and mounted on a coverslip. After that, a light microscope is used to evaluate the staining, which reveals the presence of carbohydrates like glycogen and glycoproteins.