False positives, incidentalomas, overdiagnosis

"More testing leads to more false positives and incidental findings (abnormalities that don't pose a risk to your actual health). That leads to a higher probability of treatment. And treatment carries side effects." --Charles Ornstein

And from Dr. Gilbert Welch:

The more tests you do, and this is only the statistical process, the more likely one of them will be falsely abnormal. And the more times you do it, the more chance that something will be falsely abnormal.

The problem is you'll always be catching things out of what we would say is normal. This is anticipatory medicine at its worst, where you're really focused on what could be going wrong in the future and you're trying to pick up [a] signal.

The problem is there's so much noise — because the human body is a living organism. Variation is the very essence of life. People will start reacting to this data. I also think it's really important to label it what it is: data. To me it only becomes information to the extent that it accurately predicts something will happen in the future, and it only becomes useful knowledge — a higher level piece of information — if we can do something about it.

[http://www.npr.org/blogs/health/2015/04/06/397848621/tracking-your-own-health-data-too-closely-can-make-you-sick]