Polymerase Chain Reaction-Restriction Fragment Length Polymorphism as a Confirmatory Test for Onychomycosis

BACKGROUND: Onychomycosis is a fungal infection of one or more units of the nail caused by dermatophytes, or mould and nondermatophytes yeast. Investigations are needed to establish the diagnosis of onychomycosis before starting treatment. Several investigations methods for diagnosing onychomycosis are microscopic examination with 20% KOH, fungal culture, histopathology examination with PAS staining (Periodic acid Schiff) and PCR (Polymerase Chain Reaction). Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) is a method after PCR amplification allowing more specific results. AIM: To determine the diagnostic value of PCR - RFLP in the diagnosis of onychomycosis using fungal culture as the gold standard and to find out the majority fungal species that cause onychomycosis. METHODS: This study is a diagnostic test for the diagnosis of onychomycosis by using culture as the gold standard. SUBJECTS: Thirty - five patients suspected of having onychomycosis from history and dermatological examination. RESULTS: PCR - RFLP in the diagnosis of onychomycosis has a sensitivity of 85.71%, specificity of 28.57%, positive predictive value (PPV) of 82.76% and negative predictive value (NPV) of 33.33%. The positive and negative likelihood ratios are 1.20 and 0.5 with an accuracy of 74.29%. CONCLUSIONS: PCR - RFLP may be considered for a faster and more accurate alternative examination in the diagnosis of onychomycosis.