A device for the multiplexed detection of a plurality of compounds from single cells comprising two independent components: a microwell array being a reusable device and comprising a plurality of individual microwells in uniform arrangement, the plurality of individual rectangular microwells having a length of 10-2000μm, a width of 10-100μm, and a depth of 10-100μm and configured to contain an isolated single cell in a sub-nanoliter volume of contents; and a capture agent array being a disposable test strip and comprising a plurality of immobilized capture agents, each immobilized capture agent capable of specifically binding to one of the plurality of compounds, where the immobilized capture agents are arranged in uniform capture agent sets, wherein each capture agent set comprises 10 to 50 isolated features at spatially identifiable locations, each isolated feature comprising at least one immobilized capture agent, and wherein at least one isolated feature comprises one or more immobilized capture agents, and wherein each immobilized capture agent within the isolated feature has an associated secondary capture agent with a different detectable label; wherein the microwell array and capture agent array are coupled to form a plurality of enclosed interfaces, each enclosed interface comprising a microwell and a capture agent set such that the contents of each microwell are accessible to all of the isolated features of at least one set, thereby accessible to all of the immobilized capture agents; wherein the plurality of compounds comprise at least one protein secreted from a single cell contained within a microwell, wherein the plurality of capture agents comprise an antibody; and wherein (a) each isolated feature is 25 to 30μm in width; and/or (b) each isolated feature is separated by 2 to 25μm or 25-30μm. a microwell array being a reusable device and comprising a plurality of individual microwells in uniform arrangement, the plurality of individual rectangular microwells having a length of 10-2000μm, a width of 10-100μm, and a depth of 10-100μm and configured to contain an isolated single cell in a sub-nanoliter volume of contents; and a capture agent array being a disposable test strip and comprising a plurality of immobilized capture agents, each immobilized capture agent capable of specifically binding to one of the plurality of compounds, where the immobilized capture agents are arranged in uniform capture agent sets, wherein each capture agent set comprises 10 to 50 isolated features at spatially identifiable locations, each isolated feature comprising at least one immobilized capture agent, and wherein at least one isolated feature comprises one or more immobilized capture agents, and wherein each immobilized capture agent within the isolated feature has an associated secondary capture agent with a different detectable label; wherein the microwell array and capture agent array are coupled to form a plurality of enclosed interfaces, each enclosed interface comprising a microwell and a capture agent set such that the contents of each microwell are accessible to all of the isolated features of at least one set, thereby accessible to all of the immobilized capture agents; wherein the plurality of compounds comprise at least one protein secreted from a single cell contained within a microwell, wherein the plurality of capture agents comprise an antibody; and wherein (a) each isolated feature is 25 to 30μm in width; and/or (b) each isolated feature is separated by 2 to 25μm or 25-30μm. (a) each isolated feature is 25 to 30μm in width; and/or (b) each isolated feature is separated by 2 to 25μm or 25-30μm.