Potential Hit is a Ligand Category in Single-Dose Screening of the Affinity Screening. It is a sub-category of the Inconclusive ligand category. Potential hits are those that show either Ligand-Induced Photobleaching or a negative Ligand-Induced Fluorescence Change (i.e. Quenching). These hits are called potential hits because additional Specificity Tests or Control Experiments might be necessary to distinguish a binding-induced effect on the data from a ligand-induced artifact. Note also that for the Ligand Autofluorescence category, an additional control experiment might be necessary. Autofluorescence is its own main category, however, because it has shown to be useful in the case of Ligand libraries that contain red-fluorescent substances.