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Test ID: Gram Stain (Histopathology)
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Gram Stain (Histopathology)
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Useful For
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The demonstration of gram negative and gram positive bacteria in tissue.
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Method name and description
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Gram stain. The stain colors some bacteria deep blue (Gram+) and leaves others either unstained or colored by the counterstain (Gram-). It is known that the organisms that stain deep blue have a cell wall containing teichoic acid, and those that are unstained or stain red contain lipopolysaccharides.
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Specimen type / Specimen volume / Specimen container
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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.
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Storage and transport instructions
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• Slides are stored in slide box at room temperature.
• Follow your local regulation shipping guidelines.
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Specimen Rejection Criteria
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· Broken slides
· Unlabeled slides
· Contaminated slides
· Slides/ Paraffin blocks mismatch
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Factors affecting test performance and result interpretation
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• Specimen fixation. Well fixed specimens can produced 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.
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Turnaround time / Days and times test performed / Specimen retention time
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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
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