Purpose
To provide a standardized framework for performing Modified Ziehl-Neelsen Staining.
Scope
This procedure applies to trained microbiology laboratory personnel working within an approved quality-management and biosafety system.
Principle
A modified acid-fast staining system uses altered decolorization or staining conditions to demonstrate organisms with partial or modified acid-fast characteristics.
Specimen / Test Material
Appropriately prepared specimens or smears relevant to the laboratory's validated indication.
Equipment and Materials
- Clean slides
- Validated modified ZN reagents
- Microscope
- Appropriate controls
Procedure
- Prepare and fix the smear according to the validated procedure.
- Apply the modified primary staining system.
- Decolorize using the approved modified conditions.
- Counterstain.
- Examine microscopically and document findings.
Quality Control and Quality Assurance
- Verify reagent performance.
- Use suitable controls where available.
- Follow organism-specific validated interpretation criteria.
Reporting
Report the staining reaction and relevant microscopic findings using approved terminology.
Safety
Use risk-based biosafety practices, appropriate personal protective equipment and approved decontamination and waste-disposal procedures. Treat clinical specimens and cultures according to the laboratory's biological risk assessment.
References
- World Health Organization (WHO): Toolkit for Standard Operating Procedures for Bacteriology, Mycology and Antimicrobial Susceptibility Testing.
- WHO: Laboratory Biosafety Manual, 4th edition.
- WHO guidance on collection, packaging and transport of infectious substances.
- EUCAST methodology and quality-control guidance for antimicrobial susceptibility testing, where applicable.
- Current locally approved laboratory procedures and validated manufacturer instructions.