In this paper, the in-device coexistence (IDC) interference detection is discussed for the user equipment (UE) with collocated long-term evolution (LTE) radio and WiFi radio. First, the comprehensive analysis is carried out to derive that the LTE transmission failure caused by the IDC interference from WiFi radio is related to the number of sub-frames overlapped with the WiFi transmission (called overlapped sub-frame). After that, consider the number of the detected overlapped subframes may be larger than that used to declare the serious IDC interference, an enhanced scheme is proposed to allow the enhanced NodeB (eNB) inform UE the threshold on the number of detected overlapped sub-frames. The numerical and simulation results indicate that the proposed scheme can largely reduce the detection overhead.