A dull gray appearance or lack of contrasting of the cells indicate fresh stains are needed. Water rinses should be changed after each use. Heavily chlorinated tap water can bleach out hematoxylin. It may be necessary to experiment with staining times to produce optimum results. The most powerful tool for testing Pap stains is also one of the simplest to obtain.
Buccal smears are readily available, predictable, and easy to interpret.
Dehydrate clear and coverslip without running through the counter stain. Examine the slides for nuclear detail and determine which formula and times give the best results. Times may need to be adjusted on a daily basis depending on the number of slides run through the stain. Periodically check the pH of the tap water following the hematoxylin. Counter Staining Do not allow slides to sit in the alcohol solutions following the OG and EA dyes.