These aren't a sure fire diagnosis because patients present differently and because there are changes in disease progression over time. The aqffected limb usually starts out hot, I believe and then soon settles down into cold in most cases. There may or may not be normal in between.

I was a little surprised that mine showed up so dramatically. The test was uncomfortable but mostly because I had to stand for over 15 minutes and was cold most of the time. It was not painful.