Which concept is demonstrated by the Levey-Jennings Chart?

• A. The relationship between control limits and the Gaussian distribution
• B. The trend of patient results over time
• C. The calibration accuracy of assays
• D. The effect of reagent lot changes on results

Answer: (B)

Tracking quality data over time is the essence of a Levey-Jennings chart. It plots control measurements from each run against a central value with defined limits, making any gradual trend, drift, or shift in assay performance visually obvious. This focus on changes observed over time is why it’s described as showing the trend of results as time progresses. The chart is a tool for monitoring stability of the process, not primarily about calibrating assays, showing patient results, or isolating the impact of a reagent lot change, though shifts in control results can signal issues that might be caused by those factors.