A method for detecting an interferent contribution in a biosensor is disclosed. Herein, the biosensor has a first electrode (112), a second electrode, and a third electrode (114), wherein the first electrode (112) and the second electrode are covered by a membrane, wherein the first electrode (112) further includes an enzyme or wherein the first electrode (112) is covered by an enzyme layer. Further, the first electrode (112), the second electrode, and the third electrode (114) are connected via a potentiostat, wherein, in a normal operational mode, via the potentiostat an electrical potential difference is applied between the first electrode (112) and the second electrode in a manner that the first electrode (112) allows for oxidative processes and the third electrode (114) allows for reductive processes. The method comprises the steps of: a) switching from the normal operational mode to an interferent detection mode, wherein, in the interferent detection mode, the electrical potential difference between the first electrode (112) and the second electrode is altered for a limited period of time in a manner that the third electrode (114) allows for oxidative processes; b) measuring a current-voltage characteristic (110) of the third electrode (114); and c) determining the interferent contribution in the biosensor by evaluating the current-voltage characteristic (110) of the third electrode (114). The method allows deducting the presence and, preferably, the amount of the interferent in an unambiguous way and is, generally, applicable in case of more than one kind of interferent. Neither additional working electrodes nor supplementary circuit components are required. The method is implementable within sensor electronics architectures of standard biosensors and, thus, applicable in already existing biosensor systems.