What is SPC Using Levey-Jennings Graphs?
SPC is a required Quality practice for all other types of Clinical Testing Labs except for IHC.
- Levey-Jennings charts are used in SPC to visually monitor the stability of a process over time, often in laboratory settings.
Quality control samples are run alongside patient samples, and the results are recorded. - Data Points: individual quality control results are plotted on the chart, typically over a series of runs or days.
- Mean: the average of the quality control data points is calculated and represented as a central line on the chart.
- Control Limits: statistically derived boundaries (typically +/- 1, 2, and 3 SD from the mean) that define the expected range of variation for the process.
- Interpretation: The chart is analyzed to see if the data points fall within the control limits. Points falling outside these limits may indicate a problem with the process, requiring investigation and corrective action.
