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Test ID: Periodic Acid Schiff (PAS) Stain
Periodic Acid Schiff (PAS) Stain
Useful For

Demonstration of polysaccharides, neutral mucosubstances and basement membranes.

Method name and description

Periodic Acid Schiff stain. The reaction is based on the oxidation of certain tissue elements to aldehyde periodic acid. The most common reactive group is the 1,2 gylcol group, but other groups are also selectively oxidized by periodate.

Reporting name

Periodic Acid Schiff (PAS) stain

Specimen type / Specimen volume / Specimen container

Specimen type:  Any well-fixed tissue in 10% neutral buffered formalin.

Specimen volume/ Specimen container:  Submit 3-4 µm paraffin embedded tissue section mounted on a clean glass slide.

Storage and transport instructions
  • Slides are stored in slide box at room temperature.
  • Follow your local regulation shipping guidelines.
Specimen Rejection Criteria
  • Broken slides
  • Unlabeled slides with patient/case identification
  • Contaminated slides
  • Slides/Paraffin blocks mismatch
Factors affecting test performance and result interpretation
  • Specimen fixation. Well-fixed specimens can produce consistent chemical and physical characteristics in tissue sections which allows patterns to be observed, morphological and chemical changes to be noted and comparisons made. These observations allow view of a dynamic ever-changing environment “fixed” at a particular point in time and may enable a histopathological diagnosis.
  • Paraffin section thickness. Microscopic analysis of cells and tissues requires the preparation of very thin, high quality sections (3-4 µm) mounted on a clean glass slides and appropriately stained to demonstrate normal and abnormal structures.
Turnaround time / Days and times test performed / Specimen retention time

Turnaround time: 3 hours

Days and times test performed: Once daily (Sunday to Thursday @0700-1500) 

      Note: Request received after 1100H will be run/stained the following working day.

Specimen retention time: 10 years