In our laboratory when we make smears from MGIT positive cultures, they get washed off completely during staining. We use a heat block and fix for two hours at 75 degrees. But it does not seem to help. We have tried formal milk before but it did not work as well. What could be the problem? (We clean the slices prior to use to make sure no oil residuals are present).
What other fixatives do you use in your laboratories?