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Onychomycosis Laboratory Diagnosis: Review

  • Fungal Infections of Skin and Subcutaneous Tissue (A Bonifaz, Section Editor)
  • Published:
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Purpose of Review

Onychomycosis is a growing global health problem. Proper diagnosis is important in order to avoid the risks of unnecessary treatments. This review summarizes the laboratory techniques currently available for the diagnosis of onychomycosis with the advantages and disadvantages of each test.

Recent Findings

Research is underway to prove the clinical utility of other diagnostic techniques such as PAS-stained nail biopsies and molecular tests as viable alternatives for the diagnosis of onychomycosis with promissory results.


Dermoscopy can be helpful to differentiate onychomycosis from traumatic onycholysis or true melanonychia; however, a definitive diagnosis requires the demonstration of the presence of the fungi. The combination of direct microscopy using potassium hydroxide and fungal culture is the gold standard for the diagnosis of onychomycosis; however, other alternatives, such as calcofluor white under fluorescence, PAS-stained nail biopsies, and molecular techniques have proven to be excellent methods with their advantages and limitations.

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Correspondence to Jose Manuel Rios-Yuil.

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The author declares that he has no competing interests.

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This article does not contain any studies with human or animal subjects performed by any of the authors.

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This article is part of the Topical Collection on Fungal Infections of Skin and Subcutaneous Tissue

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Rios-Yuil, J.M. Onychomycosis Laboratory Diagnosis: Review. Curr Fungal Infect Rep 11, 92–97 (2017).

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