Purpose
To perform Triple Sugar Iron (TSI) Test as part of a validated microbial identification workflow.
Scope
This procedure applies to trained microbiology laboratory personnel working within an approved quality-management and biosafety system.
Principle
Differential metabolism of carbohydrates and production of gas or hydrogen sulfide can produce characteristic reactions in TSI medium.
Specimen / Test Material
A suitable pure culture.
Equipment and Materials
- Validated biochemical test medium or reagent
- Suitable pure culture
- Incubation equipment where required
- Positive and negative controls where applicable
Procedure
- Verify isolate purity and identity.
- Confirm reagent or medium acceptability.
- Inoculate the validated TSI medium using the approved technique, incubate and interpret slant, butt, gas and other validated reactions.
- Compare findings with the laboratory-approved interpretation criteria.
- Record the result as part of the overall identification profile.
Quality Control and Quality Assurance
- Use appropriate control organisms or materials where required.
- Verify media and reagent performance.
- Do not identify an organism using a single biochemical reaction unless the validated workflow specifically permits it.
Reporting
Report the biochemical reaction using approved terminology and integrate it with the validated identification workflow.
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.