KOH with Chlorazol Black

For the direct microscopic examination of skin scrapings, hairs, nails and other clinical specimens for fungal elements.

Please note: Parker Quink permanent Ink with solvex is NO longer available, fluorescence microscopy using Calcofluor White with 10% KOH  is now the method of choice for direct microscopy of skin, hair and nail samples.


Potassium hydroxide  10 g

Glycerol  10 mL

Chlorazol Black E (0.1%) (Polysciences product number 02730-25) 10 mL

Distilled water 80 mL


Dissolve the KOH in water, then add the glycerol and Chlorazol Black. The glycerol prevents crystallisation of the reagent and prevents the specimen from drying out.

Making Mounts for Microscopy

Using sterile technique, remove a small portion of the specimen with an inoculation needle and mount in a drop of KOH on a clean microscope slide. Cover with a coverslip, squash the preparation with the butt of the inoculation needle and then blot off the excess fluid.


Negative specimens should be kept and re-examined the next day to avoid reporting false negative results due to delayed clearance and staining of the specimen.