The invention provides a method for detecting the production of one or more analytes by cells in a sample. The method uses one or more immobilized binding proteins to capture one or more analytes released from cells. The, or each, binding protein is localized at one or more discrete locations on a solid surface within a well. Cells are introduced into the well and cultured under conditions suitable for release of the analyte(s) and for binding of the analyte(s) to the binding protein(s). Restricting the binding protein(s) to one or more discrete locations within the well, rather than coating the entire surface of the well, results in increased sensitivity of the assay.
