Effects of modified sample collection technique on fungal culture yield: nail clipping/scraping versus microdrill.
OBJECTIVE: Onychomycosis requires accurate diagnosis but fungal culture yield is frequently low by routine sampling techniques. The aim of this study was to investigate the utility of nail plate/subungual microdrilling as an alternative to conventional nail clipping/subungual scraping. METHODS: Patients with clinical evidence of onychomycosis (n=46) were prospectively evaluated for fungal potassium hydroride (KOH) microscopy and culture comparing two sampling techniques: nail clipping versus microdrilling. RESULTS: Fungal cultures were positive in 48% with 2 additional cases detected by combining both methods. KOH microscopy was positive in 17% cases. Specimen obtained via the microdrill technique gave consistent heavier fungal growth on culture media. Candida species were the most common isolates (82.7% of cases) and were negative on KOH microscopy in 95 % of culture proven cases. The microdrill technique yielded consistent heavier growth on culture media CONCLUSION: Microdrill technique improves laboratory diagnosis and ultimately treatment of onychomycosis, particularly in patients with repeated KOH microscopy and culture failure despite strong clinical suspicion.