Comment by datpuz

My ex girlfriend was a doctor and we talked about this once. The gist of it that I got was that excessive early tests have a lot of risk factors that come along with them, because tests themselves being harmful (CT scans cause something like 5% of all cancers), and because false positives lead to unnecessary treatments, surgeries, medications, etc which can cause real harm. Basically, if the expected harm from the proactive testing is greater than the expected harm it would mitigate, you don't do it.