Department of Dermatology, Faculty of Medicine, Çukurova University, Adana, Turkey.
Department of Pathology, Faculty of Medicine, Çukurova University, Adana, Turkey.
Int J Dermatol. 2019 Mar;58(3):319-324. doi: 10.1111/ijd.14255. Epub 2018 Sep 23.
In the absence of a real gold standard, comparative studies are still done on diagnostic methods for onychomycosis. There are only a few attempts using latent class analysis to determine the value of polymerase chain reaction in comparison to conventional methods. We aimed to determine the value of histological examination in such a way for the diagnosis of onychomycosis.
Potassium hydroxide mount (KOH), culture and histological examination with periodic acid-Schiff (PAS), and Gomori's methenamine silver (GMS) stains were done in 106 patients having clinically suspected toenail onychomycosis.
KOH was positive in 74% of the patients; culture in 14%; PAS in 30%; and GMS in 66%. According to the results of the latent class analysis, culture and PAS were highly specific but poorly sensitive; KOH, highly sensitive but poorly specific; and GMS, both highly sensitive and specific.
Based on these results, we have proposed KOH as a screening test and GMS as a confirmatory test for the diagnosis of onychomycosis in our own practice. However, since positivity rates of different diagnostic methods vary widely in different centers, it is more suitable that every center should determine their own diagnostic strategy by evaluating their own results with latent class analysis.
在缺乏真正的金标准的情况下，仍然对甲真菌病的诊断方法进行了比较研究。只有少数尝试使用潜在类别分析来确定聚合酶链反应与常规方法相比的价值。我们旨在以这种方式确定组织学检查在甲真菌病诊断中的价值。
对 106 例临床疑似趾甲甲真菌病患者进行了氢氧化钾载玻片（KOH）、培养和过碘酸-Schiff（PAS）组织学检查以及 Gomori 的美蓝银（GMS）染色。
KOH 在 74%的患者中呈阳性；培养阳性率为 14%；PAS 阳性率为 30%；GMS 阳性率为 66%。根据潜在类别分析的结果，培养和 PAS 具有高度特异性但敏感性低；KOH 具有高度敏感性但特异性低；GMS 则具有高度敏感性和特异性。
根据这些结果，我们在自己的实践中提出了 KOH 作为筛查试验，GMS 作为甲真菌病诊断的确认试验。然而，由于不同诊断方法的阳性率在不同中心差异很大，因此每个中心通过使用潜在类别分析评估自己的结果来确定自己的诊断策略更为合适。
