Fluorescence-based methods for measuring binding are very sensitive, allow measurements in homogeneous formats, with no washing and allow for high throughput screening. The two major methods used at Affina are fluorescence polarization and fluorescence energy transfer. Fluorescence polarization (FP) requires only one of the binding partners to be labeled. The assay formats are typically homogeneous, easy to carry out and can be performed on simple plate readers with a high throughput. Time-resolved fluorescence energy transfer is highly sensitive, homogeneous and is not affected by light scattering and intrinsic fluorescence allowing for measurements in complex matrices.