Levey-Jennings chart

A Levey-Jennings chart plots sequential control results against time or run order, usually with a central mean and lines marking selected standard-deviation distances. It makes patterns in quantitative control data easier to recognize. A sudden shift may suggest a changed calibration or reagent lot, while a progressive trend may indicate deterioration or another developing process change.

The chart is a display, not a complete quality-control strategy. Interpretation depends on the source of the mean and standard deviation, the chosen decision rules, and the relationship between control behavior and patient samples. Record relevant events such as maintenance, lot changes, and recalibration. Avoid silently resetting the mean to absorb an unexplained shift, because doing so can conceal a problem that still needs investigation.

Charts provide assessors with a visible history of analytical stability and the laboratory's response to unusual patterns. Their value depends on consistent review and traceable decisions. Keep the underlying results and event notes, not just screenshots, so a reviewer can reconstruct when an issue arose, who assessed it, and how patient impact was evaluated.