It seems to be a commonly held belief that people with health care concerns always benefit from having more tests. Whether it’s blood work, an X-ray, a CT scan, an MRI or a stress test, the common refrain I hear is, “Doc, better safe than sorry!” I get that. I understand the deep human need for reassurance and confidence. When my wife had cancer several years ago, I always wanted to be certain that everything was OK. Few things felt better than a normal CT scan. And yet, sometimes more tests aren’t beneficial. Not only can they be costly, they waste time. Not only do they waste time, they can lead to unnecessary treatment (which also costs more money). Finally, they can cause actual harm to patients. For example, unnecessary blood tests requiring needle sticks in children can produce longterm anxiety about doctor visits. CT scans performed “just to be…