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KOH Preparation

Direct microscopic preparation used in validated workflows to improve visualization of fungal elements in clinical material.

Last verified 1 month ago 2 min read Microbiology Microscopy Mycology #KOH #Fungal Microscopy #Mycology
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Document Control
Version
1.0
Effective
Aug 31, 2026
Reviewed
Aug 28, 2026
Department
Microbiology
Principle

Potassium hydroxide helps clear background cellular and keratinous material, improving microscopic visualization of fungal structures when present.

Purpose

To prepare and examine a KOH mount using a validated fungal microscopy procedure.

Scope

This procedure applies to trained microbiology laboratory personnel working within an approved quality-management and biosafety system.

Principle

Potassium hydroxide helps clear background cellular and keratinous material, improving microscopic visualization of fungal structures when present.

Specimen / Test Material

Skin, hair, nail or other approved clinical material collected for direct fungal examination.

Equipment and Materials

  • Clean slides and cover glasses
  • Validated KOH preparation reagent
  • Microscope
  • Appropriate specimen collection tools

Procedure

  1. Verify specimen identity.
  2. Place an appropriate amount of specimen on a clean slide.
  3. Add the validated KOH reagent.
  4. Apply a cover glass where required.
  5. Allow clearing according to the validated procedure.
  6. Examine systematically for fungal elements.
  7. Record findings using approved terminology.

Quality Control and Quality Assurance

Use validated reagent preparation and microscopy quality checks.

Reporting

Report observed fungal elements or relevant negative findings according to laboratory policy.

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.

Frequently Asked Questions

It helps clear background material and improve visualization of fungal structures.