[Mr. Bird]

It makes no sense at all that a colonoscopy is “preventive care.” A colonoscopy doesn’t prevent anything, except a good night’s sleep and a pleasant day afterward: it is solely a diagnostic procedure. Either the view shows nothing, or it shows something that requires medical action, such as polyps or a tumor.

I'm cool with calling colonoscopies in asymptomatic patients "preventative". But if they find something and remove it, that's something else.

[Tax-chick]

I'm cool with calling colonoscopies in asymptomatic patients "preventative".

That's fine, but it's still inaccurate. A colonoscopy is looking for something wrong. That's diagnosis, by definition, even if it diagnoses nothing wrong at the present time.

A high-fiber diet is "preventative" for colon cancer, to some extent. Quitting smoking and getting more exercise are "preventative," reducing the risk of many types of cancer. Colonoscopies, x-rays, and other "Is there a cancer?" procedures are diagnostic.