This invention provides methods and systems for measuring the binding of analytes in solution to probes bound to surfaces in real-time. The method involves contacting a fluid volume having a plurality of different analytes with a solid substrate having a plurality of different probes. The probes are capable of specifically binding to the analytes. The method also involves measuring signals at multiple time points while the fluid volume is in contact with the substrate. The signals measured at multiple time points can be correlated with the amount of binding of the analytes with the probes. The method eliminates the need to wash the probes before measuring the binding characteristics.