Comment by pheewma

There are also downstream consequences of ordering tests aside from cost; not all tests are harmless. As an example, regular screening for prostate cancer isn't recommended as much. Partially because it is often so slow-growing that people often die of other causes before the cancer even begins to cancer, and because the definitive test is a biopsy which is somewhat invasive. Rates of complications are relatively low, but it becomes a cost-benefit consideration (again, irrespective of cost) of if those risks are worth catching something that you may not even want to bother treating.