Among the most important functions of a pathology or laboratory medicine service is the clear, accurate, and rapid communication of critical test results (critical values) to patient care providers. Pathologists and laboratory professionals are often confronted with many obstacles in the reporting of such critical values, including establishing clinically relevant criteria for critical values, resolving difficulties in locating an ordering provider when a critical value is obtained, and ensuring that the provider understands the severity and implications of a critical result when he or she has questions. This article presents a hypothetical (yet fairly common) clinical case scenario regarding critical values and then provides an up-to-date discussion and review of the literature on the reporting of critical results.