As a Canadian in a public health care system the doc has wasted my taxes on an unnecessary screening test, .....
But just for the pilosophical discussion:
Isn't this almost always true for screening tests that are intended to reveal rare conditions ?
Let's imagine there is some fairly expensive (or maybe even very INexpensive) test for a rare, but serious consition.
It would almost never be "cost effective" to test for it. It would always be a "better use taxpayers' money" to use the money elsewhere and let the very few sufferers of the condition degenerate and/or eventually die without ever even testing.
But if the person tested happens to be YOU, then all of a sudden it becomes very valuable to either avoid the condition or even just have the "peace of mind" that the test was negative.
What the physician does with the information (i,e. "over-medicate" etc) is a separate question; relating to the competency of the physician.
The whole situation become amplified if the patient is just trying to "optimize his health" (for bike racing, etc) because it would certainly not be cost effective to taxpayers; but it may be important to the person requesting the tests.