Commentary: diagnosis tracking and health reform.

Monitoring and feedback of diagnostic errors is essential for quality diagnosis and inimical to the direction in which the United States health delivery system is heading. Tracking diagnosis evolution longitudinally can provide rich clinical insights to improve the timeliness and accuracy of diagnosis, yet we lack even primitive systems to accomplish this function. Ten examples are listed, illustrating key questions regarding misdiagnosis. A system for tracking admitting diagnosis revision is presented as a primitive diagnosis tracking prototype. An automated system is required to generalize this system to a longitudinal outpatient setting. The perils in the implementation of diagnosis tracking include the potential for fear-inducing punitive application, tampering with appropriate diagnostic strategies due to failure to distinguish common from special cause variation, and the affixing of "price tags" to diagnoses. The latter is an especially worrisome side effect of market-driven health reform, and threatens the success of the project.