Periodic acid-Schiff (PAS) reaction
Definition
A histochemical staining method that oxidises polysaccharides (including glycogen) to produce aldehydes, which are then detected by Schiff reagent as a magenta colour. Used to detect glycogen-rich vaginal epithelial cells in smear preparations.
Related terms
- Ehrlich's reagent
- A solution of para-dimethylaminobenzaldehyde in acid. It reacts with urobilinogen and related pyrrole-containing compounds to produce a pink-red colour, used as a...
- Ferning
- The arborisation pattern formed when cervical or vaginal mucus dries on a glass slide, produced by sodium chloride and glycoprotein crystallisation. Visible...
- Glycogen
- A polysaccharide energy store present in vaginal epithelial cells. It is released when cells are lysed and can be detected by periodic...
- RSID-Vaginal Mucosa
- Rapid Stain Identification of Vaginal Mucosa. An immunochromatographic lateral-flow assay using antibodies targeting proteins specific to human vaginal epithelial cells, providing higher...
- Urobilinogen
- A colourless bile pigment metabolite produced by intestinal bacteria from bilirubin. It is excreted in faeces (as urobilin/stercobilin) and detected in forensic...
Explained in
- Vaginal Fluid and Faecal Material IdentificationA histochemical staining method that oxidises polysaccharides (including glycogen) to produce aldehydes, which are then detected by Schiff reagent as a magenta...