DAPI Counterstain is used as a counterstain for chromosomes. The counterstain consists of DAPI and antifade, which helps preserving the fluorescence signal. DAPI binds strongly to DNA, particularly to AT rich regions. It is used in the staining step of fluorescence in situ hybridization (FISH) on interphase nuclei and metaphase chromosomes. Counterstain Diluent is an antifade solution, which helps preserving the fluorescence signal. It can be used as embedding media for FISH or to dilute DAPI Counterstain when a less blue staining is preferred.