A method for detecting in-vivo properties of a biosensor, wherein the biosensor is, in interoperation with an electronics unit, adapted for electrochemically determining at least one value of an analyte in a sample of a body fluid, wherein the biosensor comprises at least one working electrode, wherein the working electrode is covered by a membrane and includes an enzyme for providing a reaction with the analyte, wherein the membrane has an electrical resistance and the working electrode has an electrical capacitance, wherein the electronics unit is adapted for measuring a raw current and a current response indicative of an admittance of the biosensor, the method comprising the steps of a) providing a sensitivity-to-admittance relation of the biosensor; b) measuring a raw current in the biosensor; c) measuring an in-vivo current response indicative of the in-vivo admittance of the biosensor, wherein the in-vivo current response is measured at at least one first operating point and at at least one second operating point, wherein the electrical capacitance C of the working electrode, and the electrical resistance R M of the membrane are determined, wherein a time constant τ is determined by the electrical capacitance C of the working electrode and the electrical resistance R M of the membrane by τ = R M · C, wherein the first operating point is selected below τ and the second operating point is selected above τ; d) determining an analyte value in a sample of a body fluid by using the raw current and compensating an in-vivo sensitivity drift in the biosensor, wherein the in-vivo drift of the biosensor is compensated by using the measured value for the raw current and a corrected value for the sensitivity, whereby the sensitivity is determined by using the sensitivity-to-admittance relation as provided during step a); and e) monitoring a failsafe operation of the biosensor by using the in-vivo current response measured at the least one first operating point and at the at least one second operating point, wherein the failsafe operation comprises a mode of operation of the biosensor selected from at least one of an indication of no valid value, a recommendation for recalibration, or a request for shut-off of the biosensor. a) providing a sensitivity-to-admittance relation of the biosensor; b) measuring a raw current in the biosensor; c) measuring an in-vivo current response indicative of the in-vivo admittance of the biosensor, wherein the in-vivo current response is measured at at least one first operating point and at at least one second operating point, wherein the electrical capacitance C of the working electrode, and the electrical resistance R M of the membrane are determined, wherein a time constant τ is determined by the electrical capacitance C of the working electrode and the electrical resistance R M of the membrane by τ = R M · C, wherein the first operating point is selected below τ and the second operating point is selected above τ; d) determining an analyte value in a sample of a body fluid by using the raw current and compensating an in-vivo sensitivity drift in the biosensor, wherein the in-vivo drift of the biosensor is compensated by using the measured value for the raw current and a corrected value for the sensitivity, whereby the sensitivity is determined by using the sensitivity-to-admittance relation as provided during step a); and e) monitoring a failsafe operation of the biosensor by using the in-vivo current response measured at the least one first operating point and at the at least one second operating point, wherein the failsafe operation comprises a mode of operation of the biosensor selected from at least one of an indication of no valid value, a recommendation for recalibration, or a request for shut-off of the biosensor.