The only test that can diagnose CRPS is a Triple phase bone scan, and at that it's only good around 65% or less of the time. As said they can use the Nerve conduction test to find areas where there is a problem that might respond to surgery or some other treatment that might help. Of course the if's are there if they find an area that shows problems, if whatever they try helps rather than hurts by causing the CRPS to spread... The one thing I know from people that have had the test done after getting CRPS is it's going to hurt like the dickens! Odds are also good that it will 'cause a flare.. Good luck with whatever you decide to do!