In one aspect the present invention provides a method for selecting a cell or cell colony which produces a polypeptide of interest, comprising a) providing a medium comprising cells and a detection agent, wherein the detection agent is associated with a detectable signal and the detection agent is capable of binding to the polypeptide of interest; b) providing a solid phase having a capture agent disposed thereon, wherein the capture agent is capable of binding to the polypeptide of interest; c) contacting the medium with the solid phase; d) detecting the signal associated with the detection agent; and e) selecting a cell or cell colony associated with the signal, wherein presence of the signal is indicative of a cell or cell colony which produces the polypeptide of interest.