I'm not a doctor, but... Well the logical thing to do is 1. Ignore mildly elevated values in the absence of symptoms. 2. Take action on very elevated values. 3. Look for trends and anomalies in the data. "This guy has had a value in the low end on every previous check up, but now it's a bit elevated, what's up with that?"

Extreme values should be treated, and 'borderline' values should be ignored, but then they often aren't. People are scared when it comes to their health.

Also a blood test and urine sample aren't invasive and come with ~0 risk.