title: PAS is optimal for diagnosing onychomycosis.
abstract: Onychomycosis is a frequently treated fungal infection of the nail plate with morbidity in high-risk populations. The diagnosis often relies on histopathologic analysis of nail plate specimens with the assistance of special stains. Pathologists utilize periodic acid schiff (PAS) and/or Gomori methenamine silver (GMS) stains to highlight fungi within the nail plate. In a recent study of 51 PAS-negative nail cases, it was concluded that GMS is superior to PAS in the diagnosis of onychomycosis. We expand on this study by investigating a larger number of PAS-negative nail clippings determining whether GMS or PAS is superior in highlighting fungi in additional sections. There was no difference in the sensitivity of PAS vs. GMS (4.2 vs. 4.3%, p = 0.57); however, PAS was found to be significantly less expensive by 2.6-fold. Taken together, these data suggest that the PAS stain is the optimal method for diagnosing onychomycosis.
authors.affiliation: Caris Research Institute, Newton, MA, USA.
authors.forename: Orr
authors.initials: O
authors.lastname: Barak
authors.forename: Adam
authors.initials: A
authors.lastname: Asarch
authors.forename: Thomas
authors.initials: T
authors.lastname: Horn
mesh_terms: D005533:Foot Dermatoses / Q000175:diagnosis*; D006229:Hand Dermatoses / Q000175:diagnosis*; D006801:Humans; D014009:Onychomycosis / Q000175:diagnosis*; D010503:Periodic Acid-Schiff Reaction / Q000191:economics; D012680:Sensitivity and Specificity; D016622:Silver Staining / Q000191:economics