A screening primer: basic principles, criteria, and pitfalls of screening with comments on colorectal carcinoma.

In this manuscript, a short review is provided of the basic principles of screening, emphasizing some of the methodologic problems attendant on any screening test, in short, a "screening primer." My analysis of the "core" data supporting efforts to screen for colorectal cancer leads to the conclusion that the utility and efficacy of screening for colorectal cancer awaits proof.