A simultaneous multianalyte electrochemical assay includes a cell which has a surface and the surface includes analyte binding sites i.e., antibodies or antigens on a solid phase at distinct separate locations. Separate working electrodes are located within proximity to these separate locations. Enzyme labeled antibodies or antigens depending on the assay format are added and the enzyme reaction product measured, by simultaneous amperometric measurement with the independent electrode in each area. The electrodes are spatially separated from adjacent analytes so that a measurement can be taken before cross-interference due to diffusion of product from adjacent analyte areas.