Laboratory medicine is a distinct medical discipline and a tool for patient care that is used in all specialties. It is based on underlying concepts that govern the proper use and interpretation of laboratory tests. This article suggests how to educate medical students about important preanalytic, analytic, and postanalytic variables that affect laboratory results. The authors postulate that laboratory medicine training requires a combination of focused lectures and a constant reinforcement of its principles throughout clinical rotations. © 2007 Elsevier Inc. All rights reserved.