A wireless power receiver including a transmitter configured to transmit to a wireless power transmitter, a foreign object detection status packet including a mode bit field indicating whether a foreign object detection status packet includes a reference peak frequency of the wireless power receiver, in which the reference peak frequency is pre-assigned to the wireless power receiver; and a receiver configured to receive from the wireless power transmitter, a response indicating the foreign object is present or not present in a charging area of the wireless power transmitter, wherein the response is determined based on a comparison of a measured peak frequency of a power signal transmitted by the wireless power transmitter and an adaptable threshold frequency adapted based on the reference peak frequency included in the foreign object detection status packet from the wireless power receiver.