In many cases, no. Pathologist Brian Jackson brings up some good points on unnecessary testing. He cites PSA test screening for prostate cancer. By itself, the test is $20, but false positives can lead to an unnecessary $1,000 prostate biopsy or $10,000 prostatectomy.
Currently, both financial and legal incentives propel doctors to order more tests, whether they are needed or not. Removing both these drivers will be the most effective way to clamp down on unnecessary testing.