COMPARISON OF YIELDS OF KOH MOUNT AND PAS STAINING OF NAIL CLIPPINGS FOR HYPHAE IN CASES OF ONYCHOMYCOSIS

Yields of KOH Mount & PAS Staining of Nail Clippings

Abstract

Objective: To compare the diagnostic yields of KOH mount and PAS staining of nail clippings for demonstration
of hyphae.
Study Design: Cross sectional study.
Place and Duration of Study: Study was conducted at dermatology department, POFs’ Hospital Wah Cantt. The
duration of the study was one year, from Aug 2016 to Aug 2017.
Material and Methods: The sample size of 60 patients was calculated using WHO calculator. Non probability
consecutive sampling was used for recruitment of participants. Patients of any age and of either sex with clinical
suspicion of onychomycosis were included in the study. Nail clippings of affected nails of each subject were
examined for hyphae after KOH mount and PAS staining. SPSS software was used for data analysis. Chi-square
test and ROC curve analysis were used for diagnostic accuracy measurement.
Results: Out of sixty patients, hyphae were seen in 49 (81.66%) after PAS staining and in 19 (31.66%) after KOH
mount. PAS staining is found to be more sensitive (80.3%) for diagnosis of onychomycosis as compared to KOH
(29.4%) (p=0.02). ROC curve analysis showed PAS had good diagnostic accuracy (ROC curve area=0.80) while
KOH had poor diagnostic accuracy (ROC curve area=0.60).
Conclusion: PAS staining of nail clippings for hyphae is a very sensitive method for diagnosis of onychomycosis
as compared to KOH mount. The current gold standard needs to be reviewed.