It's nice and well that the really good doctors don't need extra tests; unfortunately, most doctors aren't that good. So you either get the British/Canadian system, where you're screwed if the first doctor you see isn't great, or the American variant, where you get extra tests, but eventually get the proper diagnosis.
Yeah, because the world only consist of English speaking countries. You forgot Australia and New Zealand btw.
"Wer Visionen hat, sollte zum Arzt gehen." - Helmut Schmidt