title: Comparison of direct microscopy, culture and calcofluor white for the diagnosis of onychomycosis.
abstract: BACKGROUND
  Mycological diagnosis of onychomycosis can be performed by direct microcopy (KOH), cultures and calcofluor white.
  
  
  OBJECTIVE
  To compare the percentage of positivity and the degree of correlation of KOH, cultures and calcofluor white for the diagnosis of onychomycosis.
  
  
  METHODS
  Descriptive, transversal and comparative study. Samples of toenails with onychomycosis were used for KOH, cultures and calcofluor white under fluorescence. The percentage of positivity of the different techniques was calculated and the degree of correlation between them was determined (Epi Info v 3.4.3(©)).
  
  
  RESULTS
  KOH was positive in 66.67% of the cases, cultures in 33.33% and calcofluor white in 57.58%. KOH and calcofluor white had a higher percentage of positivity than culture (p<0.01 and p<0.05 respectively). The degree of correlation between KOH and calcofluor white was excellent (κ=0.8085; p<0.0001); however, the degree of correlation between KOH and culture and between calcofluor white and culture was poor.
  
  
  CONCLUSIONS
  The use of calcofluor white is not recommended in routine laboratories because it does not seem to bring any additional benefits when comparing with KOH. This is especially important when funding is a great problem.
authors: Servicio de Dermatología y Departamento de Micología, Hospital General de México, Mexico City, Mexico.
authors: Alexandro
authors: A
authors: Bonifaz
authors: José Manuel
authors: JM
authors: Rios-Yuil
authors: Roberto
authors: R
authors: Arenas
authors: Javier
authors: J
authors: Araiza
authors: Ramón
authors: R
authors: Fernández
authors: Patricia
authors: P
authors: Mercadillo-Pérez
authors: Rosa María
authors: RM
authors: Ponce-Olivera
mesh_terms: D000328:Adult; D000368:Aged; D001557:Benzenesulfonates / Q000494:pharmacology*; D002176:Candida albicans / Q000254:growth & development / Q000302:isolation & purification*; D002179:Candidiasis, Cutaneous / Q000175:diagnosis / Q000382:microbiology; D003430:Cross-Sectional Studies; D005260:Female; D005456:Fluorescent Dyes / Q000494:pharmacology*; D005533:Foot Dermatoses / Q000175:diagnosis* / Q000382:microbiology; D006801:Humans; D006878:Hydroxides / Q000494:pharmacology; D008297:Male; D008853:Microscopy; D008856:Microscopy, Fluorescence / Q000379:methods; D008875:Middle Aged; D009172:Mycology / Q000379:methods*; D014009:Onychomycosis / Q000175:diagnosis* / Q000382:microbiology; D017680:Potassium Compounds / Q000494:pharmacology; D011237:Predictive Value of Tests; D060645:Scopulariopsis / Q000254:growth & development / Q000302:isolation & purification*; D013194:Staining and Labeling / Q000379:methods*; D014034:Toes; D014249:Trichophyton / Q000254:growth & development / Q000302:isolation & purification*
chemical_list: D001557:Benzenesulfonates; D005456:Fluorescent Dyes; D006878:Hydroxides; D017680:Potassium Compounds; C007061:C.I. Fluorescent Brightening Agent 28; C029943:potassium hydroxide