A method of concurrently detecting a first analyte of interest and a second analyte of interest in a test sample comprising: contacting a solid support with the test sample comprising a first analyte of interest and a second analyte of interest, a bridge unit comprising a first and second capture reagent, and a signal detection unit comprising a third capture reagent, wherein the first analyte of interest from the sample and the second analyte of interest from the sample are different; and detecting the presence or absence of the signal detection unit which indicates the presence or absence of the first analyte of interest and second analyte of interest in the sample concurrently with a single signal, wherein the single signal is detected only when the first analyte of interest from the sample, the second analyte of interest from the sample, and the bridge unit form a bridging complex and the signal detection unit binds to bridging complex, wherein: a first capture reagent is affixed to the solid support; the first analyte of interest from the sample comprises a first interaction unit that binds to the first capture reagent and a second interaction unit that binds to the bridge unit; and the second analyte of interest from the sample comprises a first interaction unit and a second interaction unit, wherein the first interaction unit binds the first or second capture reagent of the bridge unit; wherein the first and second interaction unit of the first analyte of interest from the sample and the first and second interaction unit of the second analyte of interest from the sample are each, independently, a heterologous interaction unit wherein the heterologous interaction unit is not native to the analyte; and a signal detection unit that binds to: i) the second analyte from the sample, ii) to the second analyte's first interaction unit or second interaction unit, iii) to a component of the bridging complex, or iv) a component of an bridging complex that is only present when the complex contains the first and second analytes from the sample. contacting a solid support with the test sample comprising a first analyte of interest and a second analyte of interest, a bridge unit comprising a first and second capture reagent, and a signal detection unit comprising a third capture reagent, wherein the first analyte of interest from the sample and the second analyte of interest from the sample are different; and detecting the presence or absence of the signal detection unit which indicates the presence or absence of the first analyte of interest and second analyte of interest in the sample concurrently with a single signal, wherein the single signal is detected only when the first analyte of interest from the sample, the second analyte of interest from the sample, and the bridge unit form a bridging complex and the signal detection unit binds to bridging complex, a first capture reagent is affixed to the solid support; the first analyte of interest from the sample comprises a first interaction unit that binds to the first capture reagent and a second interaction unit that binds to the bridge unit; and the second analyte of interest from the sample comprises a first interaction unit and a second interaction unit, wherein the first interaction unit binds the first or second capture reagent of the bridge unit; wherein the first and second interaction unit of the first analyte of interest from the sample and the first and second interaction unit of the second analyte of interest from the sample are each, independently, a heterologous interaction unit wherein the heterologous interaction unit is not native to the analyte; and a signal detection unit that binds to: i) the second analyte from the sample, ii) to the second analyte's first interaction unit or second interaction unit, iii) to a component of the bridging complex, or iv) a component of an bridging complex that is only present when the complex contains the first and second analytes from the sample. i) the second analyte from the sample, ii) to the second analyte's first interaction unit or second interaction unit, iii) to a component of the bridging complex, or iv) a component of an bridging complex that is only present when the complex contains the first and second analytes from the sample.