The present disclosure refers to a method for a specific, versatile and sensitive detection of IFN-/virus-induced genes, a method for quantifying IFN potency and activity in a pharmaceutical preparation or biological sample, a method for distinguishing between IFN- and viral induction, and/or for distinguishing between different viruses, and a method for the quantification of virus activity. Also, the invention provides the necessary molecular tools like expression active response constructs, suitable cell lines, an array to perform the method and a kit.