wvmarle:
the twisting part may indeed make it quite a bit worse.
If its twisted pair ethernet cable then very likely.
At the limit, even the electronics at the end of a twisted pair ethernet cable, which has full access to the differential signals within (if that is the cables the OP has in mind) will struggle to decode.
However the OP has not owned up to exactly what it is they want to do, but the mention of 'integrity' implies checking from the outside of a cable that what ever is happening inside the cable is valid and coherent such that both ends of the cable are decoding the MAC layer correctly.
The chances of that are ...........................................