Nail Sampling techniques for Diagnosing of onychomycosis-Section 10

The clinical suspicion of onychomycosis based on appearance of the nails, requires fungal culture for confirmation. The unfamiliar terminologies used in reporting culture results leads to misinterpretation and hamper treatment decision. Accurate laboratory diagnosis of onychomycosis depends on the quality of sample collection, and reporting by microbiologist. Site selection for sampling depends on clinical suspicion of the possible pathogen. For non-dermatophyte molds, nail plate, nail bed and subungual debris provide better specimens for culture. If candida is suspected, the sample is best taken from the proximal and lateral edges of the nail. Aseptic technique prevents overgrowth of contaminants which may suppress growth of pathogenic fungi. Adequate sampling increases chances of obtaining positive results. Histopathologic examination with PAS staining is considered as gold standard test for diagnosing of onychomycosis. Direct microscopy by KOH and culture when used these two procedures in combination, would have better sensitivity than each of them alone.