Lab method
KOH preparation
Alkali clears keratin to reveal fungal elements
K-O-H prep
High-yield clue
Branching septate hyphae or 'spaghetti and meatballs' yeast on a KOH mount is the classic skin/nail fungal clue.
Overview
A wet-mount concept in which potassium hydroxide dissolves keratin and host cells so that fungal cell walls (hyphae, budding yeast, or spores) become visible under the microscope.
Classification
- Clearing agent concept
- Wet-mount light microscopy
- Fungal cell-wall visualization
- Non-specific method
Lab & identification clues
- KOH digests keratin and debris
- Hyphae and yeast walls resist alkali
- Pseudohyphae vs true hyphae vocabulary
- Often paired with calcofluor white for fluorescence
Associations
- Dermatophyte skin/nail study association
- Malassezia short hyphae and yeast pattern
- Candida pseudohyphae recognition
Commonly confused with
- Lactophenol cotton blue
- Gram stain
Your notes
Original concept summary for coursework. Sources checked: OpenStax Microbiology 2e and NCBI Bookshelf Medical Microbiology; reviewed 2026-06. Describes vocabulary and interpretation concepts only; not a lab protocol and not for handling specimens or identifying patient isolates.