What is Potassium Hydroxide Preparation for Yeast Identification?
Yeasts — predominantly Candida species and occasionally Saccharomyces or other opportunistic fungi — are part of the normal intestinal microbiota in low numbers, coexisting with commensal bacteria in a balanced ecosystem. Overgrowth occurs when antimicrobial therapy, dietary substrates high in simple sugars, immune compromise, or mucosal barrier disruption shifts the balance in favour of fungal proliferation. Potassium hydroxide clears cellular debris and rapidly dissolves human cells while preserving fungal structures, permitting direct microscopic visualisation of yeast forms and pseudohyphae. Unlike culture, KOH microscopy is a rapid point-of-care adjunct that confirms morphology but does not speciate or quantify viable organisms with precision.