Screening is a common tool used to quickly test activity of a large number of chemical or biological compounds. Commonly seen as one of the first steps within the drug discovery process, screening assays are used on large scale libraries to quickly test and select candidates that bind to or affect a desired target. Surface plasmon resonance (SPR) is often used to conduct high-throughput screening to test for real-time binding activity of a variety of biological and chemical compounds. Direct screening is one of the high-throughput assays offered on Alto, Nicoya’s digital microfluidics (DMF) based SPR instrument (Figure 1). Alto’s screening protocol allows users to establish binding activity of up to 48 unique analytes against desired targets in less than 4 hours. This technical note will go through two separate studies, with one demonstrating yes/no binding of various ligands and analytes, and the other presenting how Alto’s screening protocol can be used for the discovery of new therapeutic antibodies.