Evaluation of the usefulness of nail biopsy in the diagnosis of onychomycosis

Background: Onychomycosis affects between 2% to 30% of the world population. Nail biopsy may help in making a diagnosis and can distinguish between invasion and colonisation. Aims: To evaluate the diagnostic usefulness of nail biopsy with Periodic acid–Schiff (PAS) staining for onychomycosis, compar...

Full description

Autores:
Velásquez Agudelo V.
de Bedout Gómez C.
Cardona Arias, Jaiberth antonio
Cano Restrepo L.E.
Tipo de recurso:
Article of journal
Fecha de publicación:
2023
Institución:
Universidad Cooperativa de Colombia
Repositorio:
Repositorio UCC
Idioma:
OAI Identifier:
oai:repository.ucc.edu.co:20.500.12494/50887
Acceso en línea:
https://doi.org/10.1016/j.riam.2018.06.001
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066151712&doi=10.1016%2fj.riam.2018.06.001&partnerID=40&md5=36e9e8a56c17fc5ef2aa0e819d3fcf2c
https://hdl.handle.net/20.500.12494/50887
Palabra clave:
ADULT
ARTICLE
BIOPSY
CANDIDA PARAPSILOSIS
CLINICAL EVALUATION
COLOMBIA
DERMATOPHYTE
DIAGNOSTIC TEST
DIAGNOSTIC TEST ACCURACY STUDY
DISEASE SEVERITY
FEMALE
FUNGAL COLONIZATION
FUNGUS CULTURE
HUMAN
MAJOR CLINICAL STUDY
MALE
MIDDLE AGED
NAIL BIOPSY
NEOSCYTALIDIUM DIMIDIATUM
ONYCHOMYCOSIS
PERIODIC ACID SCHIFF STAIN
POTASSIUM HYDROXIDE
PREDICTIVE VALUE
REPRODUCIBILITY
SENSITIVITY AND SPECIFICITY
TRICHOPHYTON RUBRUM
Rights
openAccess
License
http://purl.org/coar/access_right/c_abf2
Description
Summary:Background: Onychomycosis affects between 2% to 30% of the world population. Nail biopsy may help in making a diagnosis and can distinguish between invasion and colonisation. Aims: To evaluate the diagnostic usefulness of nail biopsy with Periodic acid–Schiff (PAS) staining for onychomycosis, compared to direct KOH examination, culture and its combination in a reference laboratory in Colombia. Methods: The study included 66 patients in whom a blind and independent reading of the three tests was performed. The usefulness was defined based on the validity (sensitivity, specificity, Youden's index, likelihood ratios), performance (predictive values) efficiency (proportion of correctly diagnosed patients), and reproducibility (kappa coefficient). Results: The mean age of the patients was 55 ± 16 years, and included 76% women. The direct tests with KOH were positive in 66.7% (n = 44), 62.1% (n = 41) were positive with culture, and 56.1% (n = 37) with the biopsy. The main causal agents were non-dermatophytes moulds in 36.4% (n = 24). The most frequent species were Neoscytalidium dimidiatum (n = 11), Trichophyton rubrum (n = 11), and Candida parapsilosis (n = 13). The sensitivity of nail biopsy, when compared to the standard (KOH and/or culture), was 71%, specificity 83%, Youden's index 0.54, positive likelihood ratio 4.25, negative likelihood ratio 0.35, positive predictive value 92%, negative predictive value 52%, efficiency 74% and kappa coefficient 0.45. When biopsy was evaluated only in patients with onycholysis of the nail plate greater than 50%, all the parameters of diagnostic usefulness increased. Conclusions: The overall usefulness of the biopsy was moderate for patients with more severe symptomatology, which makes its use advisable in cases of extensive onycholysis, and when discriminating colonisation from invasion is required. © 2019 Asociación Española de Micología