A comparison of the contrast stains, Chicago blue, chlorazole black, and Parker ink, for the rapid diagnosis of skin and nail infections.
BACKGROUND
The cheapest, most rapid method for the diagnosis of mycotic skin and nail infections is direct examination of samples using a KOH preparation. The standard KOH wet mount lacks a color contrast. Various contrast dyes are available. Parker ink is one which has been extensively used, however in recent times the stain no longer provides a suitable color contrast. Two other dyes that are available are Chicago blue and chlorazole black.


METHODS
100 samples of skin or nails were prospectively examined using Chicago blue, chlorazole black, and Parker ink-KOH stains. The samples were also cultured, with culture being the diagnostic gold standard.


RESULTS
The sensitivities and specificities of the Chicago blue, chlorazole black and Parker ink stains were 78% & 96%; 63% & 97%; and 48% and 96%, respectively.


CONCLUSIONS
The Chicago blue-KOH stain provides a good color contrast and is a suitable replacement for the Parker ink-KOH stain. It is suitable for use in the dermatologist's office or in the laboratory.
Department of Microbiology and Infectious Diseases, Concord Hospital, Sydney, New South Wales, Australia. evanthia.tambosis@sswahs.nsw.gov.au
Evanthia
E
Tambosis
Christopher
C
Lim
D000438:Alcohols / Q000737:chemistry* / Q000191:economics; D001391:Azo Compounds / Q000737:chemistry* / Q000191:economics; D004396:Coloring Agents / Q000737:chemistry* / Q000191:economics; D003881:Dermatomycoses / Q000175:diagnosis*; D005557:Formaldehyde / Q000737:chemistry* / Q000191:economics; D006801:Humans; D006878:Hydroxides / Q000737:chemistry / Q000191:economics; D014009:Onychomycosis / Q000175:diagnosis*; D017680:Potassium Compounds / Q000737:chemistry / Q000191:economics; D011446:Prospective Studies; D013194:Staining and Labeling / Q000379:methods*; D014343:Trypan Blue / Q000737:chemistry* / Q000191:economics
D000438:Alcohols; D001391:Azo Compounds; D004396:Coloring Agents; D006878:Hydroxides; C019035:Parker's fluid; D017680:Potassium Compounds; D005557:Formaldehyde; C009000:pontamine sky blue; C015844:direct black 3; D014343:Trypan Blue; C029943:potassium hydroxide