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Test ID: Acid Fast Bacilli Stain
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Acid Fast Bacilli Stain
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Useful For
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Detection and demonstration of acid-fast mycobacteria in paraffin embedded tissue sections.
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Method name and description
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Ziehl-Neelsen stain. This method for acid fast bacteria is a staining technique wherein the lipoid capsule of the acid-fast organism takes up carbol-fuchsin and resists decoloration with dilute mineral acid. Carbol-fuchsin is more soluble in the lipids of the cell wall than in acid-alcohol, but it is readily removed from bacteria that lack the waxy capsule.
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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 with patient/case identification
- 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 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.
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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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