## Confirmatory Investigation for Vulvovaginal Candidiasis **Key Point:** Culture on Sabouraud dextrose agar (or other selective fungal media) is the gold standard for confirming candidiasis because it provides definitive organism identification and allows for species determination and antifungal susceptibility testing. ### Why Culture is Gold Standard 1. **Definitive identification** — grows Candida species and allows speciation (C. albicans vs. non-albicans species) 2. **Antifungal susceptibility testing** — critical in recurrent or refractory cases to guide therapy 3. **Excludes other pathogens** — rules out bacterial vaginosis or other causes 4. **Highest specificity** — 95–100% specific for candidiasis ### Comparison of Diagnostic Methods | Investigation | Sensitivity | Specificity | Clinical Use | Limitation | |---|---|---|---|---| | **Wet mount microscopy** | 40–60% | 95% | Rapid, bedside; low sensitivity | Misses 40–60% of cases | | **Culture (Sabouraud)** | 95–100% | 95–100% | Gold standard | Takes 48–72 hrs; requires lab | | **Vaginal pH** | N/A | N/A | Screening only (pH ≤4.5 in candidiasis) | Non-specific; many causes | | **Gram stain** | 50–70% | 85% | Rapid screening | Lower sensitivity than culture | **High-Yield:** In clinical practice, wet mount may be done first for rapid diagnosis, but culture on Sabouraud agar remains the gold standard for confirmation, especially in recurrent candidiasis (≥4 episodes/year) where species identification and susceptibility testing guide long-term prophylaxis. **Clinical Pearl:** Non-albicans Candida species (C. glabrata, C. auris) are increasingly common in recurrent vulvovaginal candidiasis and may show reduced susceptibility to azoles — culture identifies these and guides therapy choice (e.g., boric acid for C. glabrata). [cite:Harrison 21e Ch 198]
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