The 'Delta R' test that has been mentioned from time-to-time within the engineering fraternity, now seems to be gathering pace. Only recently, all team members on my patch were asked to complete a Broadband CBT course that skirted over this new test.
If one is to be run, it has to be done so before a PQT. Because the IR test on a PQT is carried out at 95v, this can mask or temporarily mend a HR ........... the Delta R runs at about 7v thus standing a better chance of detecting a potential HR.
I can't give any feedback on it myself as yet, as haven't needed to use it in anger.