Analysis of turnaround times in pathology: an approach using failure time analysis

This article introduces the use of failure time analysis methods for studying turnaround times in pathology. The key to understanding the approach is to view a laboratory specimen like a living patient. When the specimen enters the laboratory, the time is analogous to the time of diagnosis for a patient. When the specimen's analysis is completed, the event is analogous to a patient who has died. To illustrate the approach, I use data previously published and data generated at the Durham, NC, Veterans Affairs Medical Center. I demonstrate that the Kaplan-Meier plotting method, the log-rank test, and the Cox model can all be applied to turnaround times and provide useful results.