Wafer-level diagnosis? of RF systems at production test sites is difficult and incurs high investment cost. One possible solution for integrated RF transceivers is to loop-back the transmitted RF signal to the receiver input thereby enabling source and measure capabilities at lower frequencies using DC probe cards integrated to standard low cost test platforms. The design innovations in modern wireless transceivers limit the previously proposed loop-back methods for continuous wave signals for most GSM, ISM, WLAN and Bluetooth applications. To overcome these limitations, a novel loop-back DFT approach is proposed. When used in conjunction with ?Alternate Diagnosis?, the transmit and receive subsystem specifications can be decoupled from the final looped-back spectral signature. The key highlight of this work is that: measurements made on commercially available TI ISM microwave transceiver TRF6903 are used to demonstrate the production worthiness of the proposed approach for RF systems.