There's a reason for the growing distrust of medicine.
I generally trust my doctors. However, since they are human beings, they are as subject to confirmation bias as anyone else. Probably like more than a few people here ln /., I'm "obese" and have "metabolic syndrome." However, my cholesterol levels are where they should be, and historically always have.. even after 20 years of Type II diabetes.
However, my doctor wants to test my cholesterol every six months (even though there's absolutely no diagnostic value in doing so). Why? The logical side of me wants to just chalk it up to that "confirmation bias": I MUST have high cholesterol because I fit the profile, so the last 10 years of good cholesterol numbers don't mean anything. Additionally, my work provides free yearly cholesterol screenings as part of our corporate wellness program.. so even when I provide those lab results to the clinician he still orders a cholesterol screening.
The cynical side of me walks into the doctors office and sees freebies (pens, clipboards, etc.) advertising Lipitor and it's real hard to begin to wonder if the doctor works for me or the drug company. Somebody who's a bit more paranoid is going to see the correlation between all these cholesterol screenings and the statin drug freebies and go all Jenny McCarthy.
I deal with it the same way every time. When I go to the lab to have the actual lab work done, I decline the cholesterol test, give them a photocopy of my most recent screening from work, and ask that they add it to my chart for me.